diff --git a/README.md b/README.md index 77eb236..1079472 100644 --- a/README.md +++ b/README.md @@ -1 +1 @@ -# Visit coderolls.com +# Visit [coderolls.com](https://coderolls.com) diff --git a/collections/arraylist/README.md b/collections/arraylist/README.md new file mode 100644 index 0000000..ec09ddd --- /dev/null +++ b/collections/arraylist/README.md @@ -0,0 +1,14 @@ +# Java Collections - ArrayList in Java + +This module contains articles related to ArrayList in Java. + +## Related articles + +- [ArrayList In Java](https://coderolls.com/arraylist-in-java/) +- [How To Add An Element To ArrayList In Java?](https://coderolls.com/add-element-in-arraylist/) +- [How To Change An Element In ArrayList?](https://coderolls.com/change-element-in-arraylist/) +- [How To Remove An Element From An ArrayList?](https://coderolls.com/remove-element-from-arraylist/) +- [Iterating the ArrayList In Java](https://coderolls.com/iterating-the-arraylist-in-java/) + + +Visit [coderolls](https://coderolls.com/) to read more tutorials. diff --git a/collections/arraylist/add-element-in-arraylist/ArrayListAddExample.java b/collections/arraylist/add-element-in-arraylist/ArrayListAddExample.java new file mode 100644 index 0000000..35fe325 --- /dev/null +++ b/collections/arraylist/add-element-in-arraylist/ArrayListAddExample.java @@ -0,0 +1,33 @@ +package ArrayListAddExample; + +import java.util.ArrayList; + +/** + * A Java program to add an element at the specific index. + * + * The add(int index, E element) method will add + * an element at the specified index in ArrayList. + * + * @author Guarav Kukade at coderolls.com + * + */ +public class ArrayListAddExample { + + public static void main(String[] args) { + + ArrayList arrayList = new ArrayList(); + + //adding elements to the arrayList using normal add method + arrayList.add("Gaurav"); + arrayList.add("Shyam"); + + System.out.println(arrayList);// [Gaurav, Shyam] + + // adding an element to the arrayList at index 1 + arrayList.add(1, "Saurav"); + + System.out.println(arrayList); // [Gaurav, Saurav, Shyam] + + } + +} diff --git a/collections/arraylist/add-element-in-arraylist/ArrayListExample.java b/collections/arraylist/add-element-in-arraylist/ArrayListExample.java new file mode 100644 index 0000000..4dbdbcf --- /dev/null +++ b/collections/arraylist/add-element-in-arraylist/ArrayListExample.java @@ -0,0 +1,34 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; + +/** + * A Java program to add an element to the list. + * + * The add(E e) method will add an element to + * the end of the arrayList. + * + * @author Guarav Kukade at coderolls.com + * + */ +public class ArrayListExample { + + public static void main(String[] args) { + + ArrayList arrayList = new ArrayList(); + + //adding elements to the arrayList + arrayList.add("Gaurav"); + arrayList.add("Shyam"); + + System.out.println(arrayList);// [Gaurav, Shyam] + + // adding an element to the arrayList + // element will be added to the end of the arrayList + arrayList.add("Saurav"); + + System.out.println(arrayList); // [Gaurav, Shyam, Saurav] + + } + +} diff --git a/collections/arraylist/arraylist-addall-method-in-java/ArrayListAddAllExample.java b/collections/arraylist/arraylist-addall-method-in-java/ArrayListAddAllExample.java new file mode 100644 index 0000000..731829d --- /dev/null +++ b/collections/arraylist/arraylist-addall-method-in-java/ArrayListAddAllExample.java @@ -0,0 +1,41 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; +import java.util.List; + +/** + * A Java program to add all elements of the specified collection + * to the end of the ArrayList + * + * @author Gaurav Kukade at coderolls.com + * + */ +public class ArrayListAddAllExample { + + public static void main(String[] args) { + + // ArrayList contains actresses + List actresses1 = new ArrayList(); + + actresses1.add("Natalie Portman"); + actresses1.add("Abigail Anderson"); + actresses1.add("Jennifer Lawrence"); + + System.out.println("Actresses collection 1: \n"+ actresses1 ); + + // ArrayList contains actresses + List actresses2 = new ArrayList(); + + + + actresses2.add("Angelina Jolie"); + actresses2.add("Scarlett Johansson"); + + System.out.println("Actresses collection 2: \n"+ actresses2); + + // Add actresses2 collections all elements to actresses1 collection using addAll()method + actresses1.addAll(actresses2); + + System.out.println("Actresses : \n"+ actresses1); + } +} diff --git a/collections/arraylist/arraylist-addall-method-in-java/ArrayListAddAllExample2.java b/collections/arraylist/arraylist-addall-method-in-java/ArrayListAddAllExample2.java new file mode 100644 index 0000000..d32e64e --- /dev/null +++ b/collections/arraylist/arraylist-addall-method-in-java/ArrayListAddAllExample2.java @@ -0,0 +1,43 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; +import java.util.List; + +/** + * A Java program to add all elements of the specified collection + * to the ArrayList from a particular index + * + * @author Gaurav Kukade at coderolls.com + * + */ +public class ArrayListAddAllExample2 { + + public static void main(String[] args) { + + // ArrayList containing entrepreneurs + List entrepreneurs1 = new ArrayList(); + + entrepreneurs1.add("Bill Gates"); + entrepreneurs1.add("Steve Jobs"); + entrepreneurs1.add("Jeff Bezos"); + entrepreneurs1.add("Richard Branson"); + entrepreneurs1.add("Mark Cuban"); + + System.out.println("Entrepreneurs collection 1: \n"+ entrepreneurs1 ); + + // ArrayList containing entrepreneurs + List entrepreneurs2 = new ArrayList(); + + entrepreneurs2.add("Mark Zuckerberg"); + entrepreneurs2.add("Larry Page"); + entrepreneurs2.add("Larry Ellison"); + + System.out.println("Entrepreneurs collection 2: \n"+ entrepreneurs2); + + // Add entrepreneurs2 collections all elements to entrepreneurs1 collection + // starting from index 2 + entrepreneurs1.addAll(2, entrepreneurs2); + + System.out.println("Entrepreneurs : \n"+ entrepreneurs1); + } +} diff --git a/collections/arraylist/arraylist-clear-method-in-java/ArrayListClearMethodExample.java b/collections/arraylist/arraylist-clear-method-in-java/ArrayListClearMethodExample.java new file mode 100644 index 0000000..46b70b0 --- /dev/null +++ b/collections/arraylist/arraylist-clear-method-in-java/ArrayListClearMethodExample.java @@ -0,0 +1,38 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; +import java.util.List; + +/** + * A java program to remove all the elements + * of ArrayList using the clear() method. + * + * @author Gaurav Kukade at coderolls.com + * + */ +public class ArrayListClearMethodExample { + + public static void main(String[] args) { + + // create an arraylist cities + List cities = new ArrayList(); + + // add string objects in 'cities' + cities.add("New York City"); + cities.add("Los Angeles"); + cities.add("Mountain View"); + cities.add("Austin"); + cities.add("Atlanta"); + + // printing the cities + System.out.println("Before invoking the clear() method"); + System.out.println("Cities: "+ cities); //print the arraylist with elements + System.out.println("cities size: "+ cities.size()); + + //invoke the clear() method on arraylist + cities.clear(); + System.out.println("\nAfter invoking the clear() method"); + System.out.println("Cities: "+ cities); // empty arraylist + System.out.println("cities size: "+ cities.size()); + } +} diff --git a/collections/arraylist/arraylist-contains-method/ArrayListContainsMethodExample.java b/collections/arraylist/arraylist-contains-method/ArrayListContainsMethodExample.java new file mode 100644 index 0000000..a89aecf --- /dev/null +++ b/collections/arraylist/arraylist-contains-method/ArrayListContainsMethodExample.java @@ -0,0 +1,34 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; +import java.util.List; +/** + * A java program to check if the ArrayList + * contains the specified element. + * + * @author Gaurav Kukade a coderolls.com + * + */ +public class ArrayListContainsMethodExample { + + public static void main(String[] args) { + + //create an empty arraylist object 'states' + List states = new ArrayList(); + + //add state in the arraylist + states.add("California"); + states.add("Texas"); + states.add("Florida"); + states.add("New Jersey"); + states.add("Washington"); + + //check if states contains florida + boolean isPresent1 = states.contains("Florida"); + System.out.println("Is Florida present in the list: "+ isPresent1); + + //check if states contains alaska + boolean isPresent2 =states.contains("Alaska"); + System.out.println("\nIs Alaska present in the list: "+ isPresent2); + } +} diff --git a/collections/arraylist/arraylist-ensurecapacity-method/ArrayListEnsureCapacityExample.java b/collections/arraylist/arraylist-ensurecapacity-method/ArrayListEnsureCapacityExample.java new file mode 100644 index 0000000..e23fd9e --- /dev/null +++ b/collections/arraylist/arraylist-ensurecapacity-method/ArrayListEnsureCapacityExample.java @@ -0,0 +1,39 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; +/** + * An example java program for ensureCapacity(int MinCapacity) method + * of the ArrayList class in java. + * @author Gaurav at coderolls.com + * + */ +public class ArrayListEnsureCapacityExample { + + public static void main(String[] args) { + + // create an empty arraylist object 'states' + ArrayList states = new ArrayList<>(); + + // add state in the arraylist + states.add("California"); + states.add("Texas"); + states.add("Montana"); + states.add("Arizona"); + states.add("Florida"); + states.add("Michigan"); + states.add("New Jersey"); + states.add("Washington"); + states.add("Ohio"); + states.add("Minnesota"); + states.add("Colorado"); + states.add("Missouri"); + states.add("Nevada"); + System.out.println("ArrayList Elements are: \n"+ states); + //We need to add more states, so we will ensure + //that arraylist should hold 50 elements + states.ensureCapacity(50); + + System.out.println("\nWe ensured that the arraylist should hold 50 elements."); + } + +} diff --git a/collections/arraylist/arraylist-get-method/ArrayListGetExample.java b/collections/arraylist/arraylist-get-method/ArrayListGetExample.java new file mode 100644 index 0000000..b75cd5b --- /dev/null +++ b/collections/arraylist/arraylist-get-method/ArrayListGetExample.java @@ -0,0 +1,41 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; +import java.util.List; + +/** + * A java program to get the element by + * its index using the get() method + * + * @author Gaurav Kukade at coderolls.com + * + */ +public class ArrayListGetExample { + + public static void main(String[] args) { + + List list = new ArrayList(); + + list.add("Monday"); + list.add("Tuesday"); + list.add("Wednesday"); + list.add("Thursday"); + list.add("Friday"); + list.add("Saturday"); + list.add("Sunday"); + + System.out.println("Arraylist:"+ list); + + // get element at index 3 + String element = list.get(3); + System.out.println("\nElement at index 3 is "+ element); + + System.out.println("\nUsing get() method in for loop: \n"); + + // using the get(0 method in for loop + for(int i=0; i arrayList = new ArrayList(); + + arrayList.add("Gaurav"); + arrayList.add("Shyam"); + arrayList.add("Saurav"); + arrayList.add("Samiksha"); + arrayList.add("Rina"); + arrayList.add("Rina"); + + System.out.println(arrayList); + + } +} diff --git a/collections/arraylist/arraylist-in-java/ArrayListExample.java b/collections/arraylist/arraylist-in-java/ArrayListExample.java new file mode 100644 index 0000000..8c4b065 --- /dev/null +++ b/collections/arraylist/arraylist-in-java/ArrayListExample.java @@ -0,0 +1,26 @@ +package com.gaurav.ExProject; + +import java.util.ArrayList; + +/** + * A Java program showing arraylist maintains the insertion order. + * + * @author gaurav + * + */ +public class ArrayListExample { + + public static void main(String[] args) { + + ArrayList arrayList = new ArrayList(); + + arrayList.add("Gaurav"); + arrayList.add("Shyam"); + arrayList.add("Saurav"); + arrayList.add("Samiksha"); + arrayList.add("Rina"); + + System.out.println(arrayList); + } + +} diff --git a/collections/arraylist/arraylist-indexOf-method/ArrayListIndexOfExample.java b/collections/arraylist/arraylist-indexOf-method/ArrayListIndexOfExample.java new file mode 100644 index 0000000..43b8260 --- /dev/null +++ b/collections/arraylist/arraylist-indexOf-method/ArrayListIndexOfExample.java @@ -0,0 +1,38 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; +import java.util.List; + +/** + * A java program to explain the indexOf() method + * of the arrayList class in java. + * + * @author Gaurav Kukade + */ +public class ArrayListIndexOfExample { + + public static void main(String[] args) { + + // create an empty arraylist object 'states' + List states = new ArrayList(); + + // add state in the arraylist, Florida multiple times + states.add("California"); + states.add("Texas"); + states.add("Florida"); + states.add("Florida"); + states.add("New Jersey"); + states.add("Washington"); + states.add("Florida"); + + int index = states.indexOf("Florida"); + + //prints index of the first occurrences of Florida i.e. 2 + System.out.println("The index of the Florida: "+ index); + + //trying get the index of element, which is not present + int index2 = states.indexOf("Alaska"); + + System.out.println("The index of the Alaska: " + index2); + } +} diff --git a/collections/arraylist/arraylist-isempty-method/ArrayListIsEmptyExample.java b/collections/arraylist/arraylist-isempty-method/ArrayListIsEmptyExample.java new file mode 100644 index 0000000..886e31e --- /dev/null +++ b/collections/arraylist/arraylist-isempty-method/ArrayListIsEmptyExample.java @@ -0,0 +1,44 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; +/** + * An example java program for an isEmpty method + * of the ArrayList class in java. + * + * @author Gaurav Kukade at coderolls + */ +public class ArrayListIsEmptyExample { + + public static void main(String[] args) { + + // create an arraylyst teams + ArrayList teams = new ArrayList(); + + // add elements to the arraylist teams + teams.add("LA Galaxy"); + teams.add("Orlando City FC"); + teams.add("Portland Timbers"); + teams.add("Columbus Crew"); + + boolean isTeamsEmpty = teams.isEmpty(); + + if(isTeamsEmpty) { + System.out.println("Teams arraylist is empty."); + } + else { + System.out.println("Teams arraylist is not empty."); + } + + // create an arraylist players + ArrayList players = new ArrayList(); + + boolean isPlayersEmpty = players.isEmpty(); + + if(isPlayersEmpty) { + System.out.println("Players arraylist is empty."); + } + else { + System.out.println("Players arraylist is not empty."); + } + } +} diff --git a/collections/arraylist/arraylist-lastindexof-method/ArrayListLastIndexOfExample.java b/collections/arraylist/arraylist-lastindexof-method/ArrayListLastIndexOfExample.java new file mode 100644 index 0000000..52ff0ab --- /dev/null +++ b/collections/arraylist/arraylist-lastindexof-method/ArrayListLastIndexOfExample.java @@ -0,0 +1,39 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; +import java.util.List; + +/** + * A java program to explain the indexOf() method + * of the arrayList class in java. + * + * @author Gaurav Kukade + */ +public class ArrayListLastIndexOfExample { + +public static void main(String[] args) { + + // create an empty arraylist object 'states' + List states = new ArrayList(); + + // add state in the arraylist, Florida multiple times + states.add("California"); + states.add("Texas"); + states.add("Florida"); + states.add("Florida"); + states.add("New Jersey"); + states.add("Washington"); + states.add("Florida"); + + int index = states.lastIndexOf("Florida"); + + //prints index of the last occurrences of Florida i.e. 6 + System.out.println("The last index of the Florida: "+ index); + + //trying get the index of element, which is not present + int index2 = states.lastIndexOf("Alaska"); + + System.out.println("The index of the Alaska: " + index2); + } + +} \ No newline at end of file diff --git a/collections/arraylist/arraylist-listiterator-method/ArrayListListIteratorExample.java b/collections/arraylist/arraylist-listiterator-method/ArrayListListIteratorExample.java new file mode 100644 index 0000000..d25c5b1 --- /dev/null +++ b/collections/arraylist/arraylist-listiterator-method/ArrayListListIteratorExample.java @@ -0,0 +1,35 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; +import java.util.ListIterator; +/** + * An example java program about the listIterator() + * method of the arrayList. + * + * @author coderolls.com + */ +public class ArrayListListIteratorExample { + + public static void main(String[] args) { + + ArrayList states = new ArrayList<>(); + + // add state in the arraylist + states.add("California"); + states.add("Texas"); + states.add("Montana"); + states.add("Arizona"); + states.add("Florida"); + states.add("Michigan"); + states.add("New Jersey"); + states.add("Washington"); + states.add("Ohio"); + + ListIterator itr = states.listIterator(); + + while(itr.hasNext()) { + String state = itr.next(); + System.out.println("The state :"+ state); + } + } +} diff --git a/collections/arraylist/arraylist-listiterator-method/ArrayListListIteratorExample2.java b/collections/arraylist/arraylist-listiterator-method/ArrayListListIteratorExample2.java new file mode 100644 index 0000000..3f9c41e --- /dev/null +++ b/collections/arraylist/arraylist-listiterator-method/ArrayListListIteratorExample2.java @@ -0,0 +1,36 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; +import java.util.ListIterator; +/** + * An example java program about the listIterator() + * method of the arrayList. + * + * @author coderolls.com + */ +public class ArrayListListIteratorExample2 { + + public static void main(String[] args) { + + ArrayList states = new ArrayList<>(); + + // add state in the arraylist + states.add("California"); + states.add("Texas"); + states.add("Montana"); + states.add("Arizona"); + states.add("Florida"); + states.add("Michigan"); + states.add("New Jersey"); + states.add("Washington"); + states.add("Ohio"); + + //given index 3 iterator start from element with index 3 + ListIterator itr = states.listIterator(3); + + while(itr.hasNext()) { + String state = itr.next(); + System.out.println("The state :"+ state); + } + } +} diff --git a/collections/arraylist/arraylist-listiterator-method/ArrayListListIteratorException.java b/collections/arraylist/arraylist-listiterator-method/ArrayListListIteratorException.java new file mode 100644 index 0000000..a62a1cb --- /dev/null +++ b/collections/arraylist/arraylist-listiterator-method/ArrayListListIteratorException.java @@ -0,0 +1,36 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; +import java.util.ListIterator; +/** + * An example java program about the listIterator() + * method of the arrayList. + * + * @author coderolls.com + */ +public class ArrayListListIteratorException { + + public static void main(String[] args) { + + ArrayList states = new ArrayList<>(); + + // add state in the arraylist + states.add("California"); + states.add("Texas"); + states.add("Montana"); + states.add("Arizona"); + states.add("Florida"); + states.add("Michigan"); + states.add("New Jersey"); + states.add("Washington"); + states.add("Ohio"); + + //given index 120, it will throw IndexOutOfBoundsException + ListIterator itr = states.listIterator(120); + + while(itr.hasNext()) { + String state = itr.next(); + System.out.println("The state :"+ state); + } + } +} diff --git a/collections/arraylist/arraylist-removeall-method/ArrayListRemoveAllExample.java b/collections/arraylist/arraylist-removeall-method/ArrayListRemoveAllExample.java new file mode 100644 index 0000000..0033f0c --- /dev/null +++ b/collections/arraylist/arraylist-removeall-method/ArrayListRemoveAllExample.java @@ -0,0 +1,49 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; +import java.util.List; +import java.util.function.Predicate; + +/** + * A java program showing an example for the removeAll() + * method of the ArrayList class in Java. + * + * @author gaurav + */ +public class ArrayListRemoveAllExample { + + public static void main(String[] args) { + + // create an empty arraylist object 'states' + List states = new ArrayList(); + + // add state in the arraylist, Florida multiple times + states.add("California"); + states.add("Texas"); + states.add("Montana"); + states.add("Arizona"); + states.add("Florida"); + states.add("Michigan"); + states.add("New Jersey"); + states.add("Washington"); + states.add("Ohio"); + states.add("Minnesota"); + states.add("Colorado"); + states.add("Missouri"); + states.add("Nevada"); + + // create another ArrayList for items to be removed + List statesToBeRemoved = new ArrayList(); + statesToBeRemoved.add("Minnesota"); + statesToBeRemoved.add("Missouri"); + statesToBeRemoved.add("Montana"); + statesToBeRemoved.add("Michigan"); + + System.out.println("The states list before the removeAll() method call: \n" + states); + + // removes all elements specified in the ArrayList statesToBeRemoved + states.removeAll(statesToBeRemoved); + + System.out.println("\nThe states list after the removeAll() method call: \n" + states); + } +} diff --git a/collections/arraylist/arraylist-removeall-method/ArrayListRemoveAllNullPointerException.java b/collections/arraylist/arraylist-removeall-method/ArrayListRemoveAllNullPointerException.java new file mode 100644 index 0000000..c6dbb56 --- /dev/null +++ b/collections/arraylist/arraylist-removeall-method/ArrayListRemoveAllNullPointerException.java @@ -0,0 +1,46 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; +import java.util.List; +import java.util.function.Predicate; + +/** + * A java program showing a NullPointerException case + * for the removeAll() method of the ArrayList class in Java. + * + * @author gaurav + */ +public class ArrayListRemoveAllNullPointerException { + + public static void main(String[] args) { + + // create an empty arraylist object 'states' + List states = new ArrayList(); + + // add state in the arraylist, Florida multiple times + states.add("California"); + states.add("Texas"); + states.add("Montana"); + states.add("Arizona"); + states.add("Florida"); + states.add("Michigan"); + states.add("New Jersey"); + states.add("Washington"); + states.add("Ohio"); + states.add("Minnesota"); + states.add("Colorado"); + states.add("Missouri"); + states.add("Nevada"); + + // create another ArrayList with null value, + //so that removeAll will throw NullPointerException + List statesToBeRemoved =null; + + System.out.println("The states list before the removeAll() method call: \n" + states); + + // removes all elements specified in the ArrayList statesToBeRemoved + states.removeAll(statesToBeRemoved); + + System.out.println("\nThe states list after the removeAll() method call: \n" + states); + } +} diff --git a/collections/arraylist/arraylist-removeif-method/ArrayListRemoveIfExample.java b/collections/arraylist/arraylist-removeif-method/ArrayListRemoveIfExample.java new file mode 100644 index 0000000..27c0c29 --- /dev/null +++ b/collections/arraylist/arraylist-removeif-method/ArrayListRemoveIfExample.java @@ -0,0 +1,37 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; +import java.util.List; +import java.util.function.Predicate; + +/** + * A java program showing an example for the removeIf() + * method of the ArrayList class in Java. + * + * @author gaurav + */ +public class ArrayListRemoveIfExample { + + public static void main(String[] args) { + + // create an empty arraylist object 'states' + List states = new ArrayList(); + + // add state in the arraylist, Florida multiple times + states.add("California"); + states.add("Texas"); + states.add("Florida"); + states.add("Florida"); + states.add("New Jersey"); + states.add("Washington"); + states.add("Florida"); + + System.out.println("The states list before the removeIf() call: \n" + states); + + // a predicate for the condition + Predicate p = s -> s.equals("Florida"); + states.removeIf(p); // removes all elements which satisfy the predicate p + + System.out.println("\nThe states list after the removeIf() call: \n" + states); + } +} diff --git a/collections/arraylist/arraylist-removerange-method/MyArrayList.java b/collections/arraylist/arraylist-removerange-method/MyArrayList.java new file mode 100644 index 0000000..a6bcc81 --- /dev/null +++ b/collections/arraylist/arraylist-removerange-method/MyArrayList.java @@ -0,0 +1,37 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; +import java.util.List; + +/** + * A java program to remove the range of elements from + * the MyArraylist (a class which extends the ArrayList) + * using the removeRange() method. + * + * The removeRange() method is protected and is accessed in class, + * subclasses and in a package, but not public. + * + * @author Gaurav Kukade at coderolls.com + * + */ +public class MyArrayList extends ArrayList { + + public static void main(String[] args) { + + MyArrayList myArrayList = new MyArrayList(); + + myArrayList.add("Monday"); + myArrayList.add("Tuesday"); + myArrayList.add("Wednesday"); + myArrayList.add("Thursday"); + myArrayList.add("Friday"); + myArrayList.add("Saturday"); + myArrayList.add("Sunday"); + + System.out.println("Arraylist before removing range of elments:\n"+ myArrayList); + + myArrayList.removeRange(2, 4); + + System.out.println("\nArraylist after removing range of elments:\n"+ myArrayList); + } +} diff --git a/collections/arraylist/arraylist-retainall-method/ArrayListRetainAllExample.java b/collections/arraylist/arraylist-retainall-method/ArrayListRetainAllExample.java new file mode 100644 index 0000000..265abbe --- /dev/null +++ b/collections/arraylist/arraylist-retainall-method/ArrayListRetainAllExample.java @@ -0,0 +1,51 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; +import java.util.List; + +/** + * A java program to to eplain the retainAll() method of the Arraylist class. + * + * @author Gaurav Kukade at coderolls.com + * + */ +public class ArrayListRetainAllExample { + + public static void main(String[] args) { + + //create an empty arraylist of Integer to retain elements + List numbers1 = new ArrayList(); + + //add number to the list + numbers1.add(4); + numbers1.add(5); + numbers1.add(6); + + + //create an empty arraylist of Integer + List numbers2 = new ArrayList(); + + // add number to the list + numbers2.add(1); + numbers2.add(2); + numbers2.add(3); + numbers2.add(4); + numbers2.add(5); + numbers2.add(6); + numbers2.add(7); + numbers2.add(8); + numbers2.add(9); + + + System.out.println("Lists before the method call"); + System.out.println("numbers1: "+ numbers1); + System.out.println("numbers2: "+ numbers2); + + //retain all the elements of numbers1 in the list numbers2 + numbers2.retainAll(numbers1); + + System.out.println("\nLists after the method call"); + System.out.println("numbers1: "+ numbers1); + System.out.println("numbers2: "+ numbers2); + } +} diff --git a/collections/arraylist/arraylist-retainall-method/RetainAllNullPointerExceptionExample.java b/collections/arraylist/arraylist-retainall-method/RetainAllNullPointerExceptionExample.java new file mode 100644 index 0000000..942c2ed --- /dev/null +++ b/collections/arraylist/arraylist-retainall-method/RetainAllNullPointerExceptionExample.java @@ -0,0 +1,39 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; +import java.util.List; +/** + * A java program to show the NullPointerException in retainAll() method + * of the arrayList class. + * + * @author gaurav + * + */ +public class RetainAllNullPointerExceptionExample { + + public static void main(String[] args) { + + //create an empty arraylist of Integer to retain elements + List numbers1 = null; + + //create an empty arraylist of Integer + List numbers2 = new ArrayList(); + + // add number to the list + numbers2.add(1); + numbers2.add(2); + numbers2.add(3); + numbers2.add(4); + + System.out.println("Lists before the method call"); + System.out.println("numbers1: "+ numbers1); + System.out.println("numbers2: "+ numbers2); + + //retain all the elements of numbers1 in the list numbers2 + numbers2.retainAll(numbers1); + + System.out.println("\nLists after the method call"); + System.out.println("numbers1: "+ numbers1); + System.out.println("numbers2: "+ numbers2); + } +} diff --git a/collections/arraylist/change-element-in-arraylist/ArrayListSetExample.java b/collections/arraylist/change-element-in-arraylist/ArrayListSetExample.java new file mode 100644 index 0000000..245ffc3 --- /dev/null +++ b/collections/arraylist/change-element-in-arraylist/ArrayListSetExample.java @@ -0,0 +1,34 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; + +/** + * A java program to change an element at + * particular index in ArrayList. + * + * We can use 'public E set(int index, E element)' method + * to change an element. + * + * @author Guarav Kukade at coderolls.com + * + */ +public class ArrayListSetExample { + + public static void main(String[] args) { +ArrayList arrayList = new ArrayList(); + + //adding elements to the arrayList using normal add method + arrayList.add("Gaurav"); + arrayList.add("Shyam"); + arrayList.add("Pradnya"); + + System.out.println(arrayList);// [Gaurav, Shyam, Pradnya] + + // change an element at index 1 + arrayList.set(1, "Saurav"); + + System.out.println(arrayList); // [Gaurav, Saurav, Pradnya] + + } + +} diff --git a/collections/arraylist/convert-arraylist-to-array/ArrayListToArray.java b/collections/arraylist/convert-arraylist-to-array/ArrayListToArray.java new file mode 100644 index 0000000..1e0fd8b --- /dev/null +++ b/collections/arraylist/convert-arraylist-to-array/ArrayListToArray.java @@ -0,0 +1,39 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; + +/** + * A java program to convert an ArrayList to array using + * toArray method. + * + * toArray() method returns Object[] + * + * @author Gaurav Kukade at coderolls.com + * + */ +public class ArrayListToArray { + + public static void main(String[] args) { + ArrayList arrayList = new ArrayList(); + + //adding elements to the arrayList + arrayList.add("Meta"); + arrayList.add("Apple"); + arrayList.add("Amazon"); + arrayList.add("Netflix"); + arrayList.add("Microsoft"); + arrayList.add("Google"); + + System.out.println("ArrayList: \n"+ arrayList); + + // convert ArrayList to array + Object[] objects = arrayList.toArray(); + + System.out.println("\nArray:"); + + //we will receive the object array, so iterate on it to print each element + for(Object obj:objects) { + System.out.println(obj); + } + } +} diff --git a/collections/arraylist/convert-arraylist-to-array/ArrayListToArray2.java b/collections/arraylist/convert-arraylist-to-array/ArrayListToArray2.java new file mode 100644 index 0000000..88b17da --- /dev/null +++ b/collections/arraylist/convert-arraylist-to-array/ArrayListToArray2.java @@ -0,0 +1,42 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; + +/** + * A java program to convert an ArrayList to array using + * toArray method. + * + * toArray(T[] a) method returns T[] + * + * @author Gaurav Kukade at coderolls.com + * + */ +public class ArrayListToArray2 { + + public static void main(String[] args) { + ArrayList arrayList = new ArrayList(); + + //adding elements to the arrayList + arrayList.add("Meta"); + arrayList.add("Apple"); + arrayList.add("Amazon"); + arrayList.add("Netflix"); + arrayList.add("Microsoft"); + arrayList.add("Google"); + + System.out.println("ArrayList: \n"+ arrayList); + + // convert ArrayList to array + // pass a new String array of the arrayList size as a param to toArray + //String[] elements = arrayList.toArray(new String[arrayList.size()]); + + //kindly read the 'Important Note' below + String[] elements = arrayList.toArray(new String[0]); + + System.out.println("\nArray:"); + //we will receive the string array, so iterate on it to print each element + for(String str:elements) { + System.out.println(str); + } + } +} diff --git a/collections/arraylist/iterating-the-arraylist-in-java/ArrayListIterateExample1.java b/collections/arraylist/iterating-the-arraylist-in-java/ArrayListIterateExample1.java new file mode 100644 index 0000000..b18f159 --- /dev/null +++ b/collections/arraylist/iterating-the-arraylist-in-java/ArrayListIterateExample1.java @@ -0,0 +1,33 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; +import java.util.List; + +/** + * A java program to iterate through arraylist + * using the basic for loop. + * + * @author Gaurav Kukade at coderolls.com + * + */ +public class ArrayListIterateExample1 { + + public static void main (String[] args) { + + List list = new ArrayList(); + + list.add("Monday"); + list.add("Tuesday"); + list.add("Wednesday"); + list.add("Thursday"); + list.add("Friday"); + list.add("Saturday"); + list.add("Sunday"); + + System.out.println("Iterating through ArrayList using the basic for loop.......\n"); + + for(int i =0; i list = new ArrayList(); + + list.add("Monday"); + list.add("Tuesday"); + list.add("Wednesday"); + list.add("Thursday"); + list.add("Friday"); + list.add("Saturday"); + list.add("Sunday"); + + System.out.println("Iterating through ArrayList using enhanced for loop i.e. For-each loop.......\n"); + + for(String str:list){ + //we get 'str' in for-each loop + System.out.println("Object form the ArrayList is " + str); + } + } +} \ No newline at end of file diff --git a/collections/arraylist/iterating-the-arraylist-in-java/ArrayListIterateExample3.java b/collections/arraylist/iterating-the-arraylist-in-java/ArrayListIterateExample3.java new file mode 100644 index 0000000..9726af2 --- /dev/null +++ b/collections/arraylist/iterating-the-arraylist-in-java/ArrayListIterateExample3.java @@ -0,0 +1,36 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; +import java.util.List; + +/** + * A java program to iterate through arraylist + * using while loop. + * + * @author Gaurav Kukade at coderolls.com + * + */ +public class ArrayListIterateExample3 { + + public static void main (String[] args) { + + List list = new ArrayList(); + + list.add("Monday"); + list.add("Tuesday"); + list.add("Wednesday"); + list.add("Thursday"); + list.add("Friday"); + list.add("Saturday"); + list.add("Sunday"); + + System.out.println("Iterating through ArrayList using while loop.......\n"); + + int i=0; + // while loop condition will be true till i is less the the list size + while (list.size()>i) { + System.out.println("Object form the ArrayList at "+ i + " is " + list.get(i)); + i++; + } + } +} \ No newline at end of file diff --git a/collections/arraylist/iterating-the-arraylist-in-java/ArrayListIterateExample4.java b/collections/arraylist/iterating-the-arraylist-in-java/ArrayListIterateExample4.java new file mode 100644 index 0000000..629f3ea --- /dev/null +++ b/collections/arraylist/iterating-the-arraylist-in-java/ArrayListIterateExample4.java @@ -0,0 +1,41 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; +import java.util.Iterator; +import java.util.List; + +/** + * A java program to iterate through arraylist + * using Iterator interface. + * + * @author Gaurav Kukade at coderolls.com + * + */ +public class ArrayListIterateExample4 { + + public static void main (String[] args) { + + List list = new ArrayList(); + + list.add("Monday"); + list.add("Tuesday"); + list.add("Wednesday"); + list.add("Thursday"); + list.add("Friday"); + list.add("Saturday"); + list.add("Sunday"); + + System.out.println("Iterating through ArrayList using Iterator interface........\n"); + + // getting iterator + Iterator iterator = list.iterator(); + + // hasNext() returns true only if object is available at next call + while (iterator.hasNext()) { + + //next() returns obejct, we can cast it to reuqired type + String str = (String) iterator.next(); + System.out.println("Object form the ArrayList is " + str); + } + } +} \ No newline at end of file diff --git a/collections/arraylist/iterating-the-arraylist-in-java/ArrayListIterateExample5.java b/collections/arraylist/iterating-the-arraylist-in-java/ArrayListIterateExample5.java new file mode 100644 index 0000000..fc7b89d --- /dev/null +++ b/collections/arraylist/iterating-the-arraylist-in-java/ArrayListIterateExample5.java @@ -0,0 +1,32 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; +import java.util.List; + +/** + * A java program to iterate through arraylist + * using forEach method and lamda expression. + * + * @author Gaurav Kukade at coderolls.com + * + */ +public class ArrayListIterateExample5 { + + public static void main (String[] args) { + + List list = new ArrayList(); + + list.add("Monday"); + list.add("Tuesday"); + list.add("Wednesday"); + list.add("Thursday"); + list.add("Friday"); + list.add("Saturday"); + list.add("Sunday"); + + System.out.println("Iterating through ArrayList using forEach method and lamda expression........\n"); + + // add lambda expressionin the foreach loop + list.forEach(s -> System.out.println("Object form the ArrayList is "+ s)); + } +} \ No newline at end of file diff --git a/collections/arraylist/remove-element-from-arraylist/ArrayListRemoveExample.java b/collections/arraylist/remove-element-from-arraylist/ArrayListRemoveExample.java new file mode 100644 index 0000000..65c87a3 --- /dev/null +++ b/collections/arraylist/remove-element-from-arraylist/ArrayListRemoveExample.java @@ -0,0 +1,30 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; + +/** + * A Java program to remove an element from ArrayList + * using the remove(Object o) method. + * + * @author Gaurav Kukade at coderolls.com + * + */ +public class ArrayListRemoveExample { + + public static void main(String[] args) { + + ArrayList arrayList = new ArrayList(); + + //adding elements to the arrayList using normal add method + arrayList.add("Red"); + arrayList.add("Green"); + arrayList.add("Pink"); + + System.out.println("ArrayList before removing an element"+ arrayList); // ArrayList before removing an element[Red, Green, Pink] + + //Remove "Pink" from the arrayList + arrayList.remove("Pink"); + + System.out.println("ArrayList after removing an element"+ arrayList);// ArrayList after removing an element[Red, Green] + } +} diff --git a/collections/arraylist/remove-element-from-arraylist/ArrayListRemoveExample2.java b/collections/arraylist/remove-element-from-arraylist/ArrayListRemoveExample2.java new file mode 100644 index 0000000..b9f098a --- /dev/null +++ b/collections/arraylist/remove-element-from-arraylist/ArrayListRemoveExample2.java @@ -0,0 +1,32 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; + +/** + * A Java program to remove an element from ArrayList + * using the remove(int index) method. + * + * @author Gaurav Kukade at coderolls.com + * + */ +public class ArrayListRemoveExample2 { + + public static void main(String[] args) { + + ArrayList arrayList = new ArrayList(); + + //adding elements to the arrayList using normal add method + arrayList.add("Apple"); + arrayList.add("Orange"); + arrayList.add("Guava"); + arrayList.add("Banana"); + + System.out.println("ArrayList before removing an element"+ arrayList); // ArrayList before removing an element[Apple, Orange, Guava, Banana] + + //Remove the element at the specified index i.e. 2 + //Remove "Guava" from the arrayList + arrayList.remove(2); + + System.out.println("ArrayList after removing an element"+ arrayList);// ArrayList after removing an element[Apple, Orange, Banana] + } +} diff --git a/collections/arraylist/remove-element-from-arraylist/ArrayListRemoveObjectExample.java b/collections/arraylist/remove-element-from-arraylist/ArrayListRemoveObjectExample.java new file mode 100644 index 0000000..1519655 --- /dev/null +++ b/collections/arraylist/remove-element-from-arraylist/ArrayListRemoveObjectExample.java @@ -0,0 +1,35 @@ +package com.gaurav.ExProject2; + +import java.util.ArrayList; +/** + * A Java program to remove an object from ArrayList + * using the remove(int index) method. + * + * @author Gaurav Kukade at coderolls.com + * + */ +public class ArrayListRemoveObjectExample { + + public static void main(String[] args) { + + ArrayList arrayList = new ArrayList(); + + //create Employee objects + Employee john = new Employee(100, "John Doe", 20000); + Employee nathasha = new Employee(101, "Natasha Putin", 28000); + Employee remo = new Employee(102, "Remo Smith", 40000); + + //adding employee objects to the arrayList using normal add method + arrayList.add(john); + arrayList.add(nathasha); + arrayList.add(remo); + + System.out.println("ArrayList before removing an employee Object:\n"+ arrayList); + + //Remove object using the remo0ve(Object o) method + //Remove employee nathasha from the arrayList + arrayList.remove(nathasha); + + System.out.println("\nArrayList after removing an employee Object:\n"+ arrayList); + } +} diff --git a/collections/arraylist/remove-element-from-arraylist/ArrayListRemoveObjectExample2.java b/collections/arraylist/remove-element-from-arraylist/ArrayListRemoveObjectExample2.java new file mode 100644 index 0000000..7117524 --- /dev/null +++ b/collections/arraylist/remove-element-from-arraylist/ArrayListRemoveObjectExample2.java @@ -0,0 +1,36 @@ +package com.gaurav.ExProject2; + +import java.util.ArrayList; + +/** + * A Java program to remove an object from ArrayList + * using the remove(int index) method. + * + * @author Gaurav Kukade at coderolls.com + * + */ +public class ArrayListRemoveObjectExample2 { + + public static void main(String[] args) { + + ArrayList arrayList = new ArrayList(); + + //create Employee objects + Employee john = new Employee(100, "John Doe", 20000); + Employee nathasha = new Employee(101, "Natasha Putin", 28000); + Employee remo = new Employee(102, "Remo Smith", 40000); + + //adding employee objects to the arrayList using normal add method + arrayList.add(john); + arrayList.add(nathasha); + arrayList.add(remo); + + System.out.println("ArrayList before removing an employee Object:\n"+ arrayList); + + //Remove object using the remove(int index) method + //Remove employee nathasha from the arrayList, so pass natasha's index + arrayList.remove(1); + + System.out.println("\nArrayList after removing an employee Object:\n"+ arrayList); + } +} diff --git a/collections/arraylist/remove-element-from-arraylist/Employee.java b/collections/arraylist/remove-element-from-arraylist/Employee.java new file mode 100644 index 0000000..0e63c8f --- /dev/null +++ b/collections/arraylist/remove-element-from-arraylist/Employee.java @@ -0,0 +1,52 @@ +package com.gaurav.ExProject2; +/** + * An employee class for ArrayList remove example + * @author Gaurav Kukade at coderolls.com + * + */ +public class Employee { + + private int id; + + private String name; + + private int salary; + + // a constructor will all the fields + public Employee(int id, String name, int salary) { + this.id = id; + this.name = name; + this.salary = salary; + } + + // getters and setters for the variables + public int getId() { + return id; + } + + public void setId(int id) { + this.id = id; + } + + public String getName() { + return name; + } + + public void setName(String name) { + this.name = name; + } + + public int getSalary() { + return salary; + } + + public void setSalary(int salary) { + this.salary = salary; + } + + // Override to string method to print student objects + @Override + public String toString() { + return "{"+this.getId()+", "+ this.getName()+ ", "+this.getSalary()+"}"; + } +} diff --git a/collections/arraylist/sublist-method-in-arraylist/ArrayListSubListExample.java b/collections/arraylist/sublist-method-in-arraylist/ArrayListSubListExample.java new file mode 100644 index 0000000..8a222ed --- /dev/null +++ b/collections/arraylist/sublist-method-in-arraylist/ArrayListSubListExample.java @@ -0,0 +1,33 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; +import java.util.List; + +/** + * A java program to explain the subList() method of the ArrayList class in Java + * + * @author Gaurav Kukade at coderolls.com + * + */ +public class ArrayListSubListExample { + + public static void main(String[] args) { + + // create an empty arraylist object 'states' + List states = new ArrayList(); + + // add state in the arraylist + states.add("California"); + states.add("Texas"); + states.add("Florida"); + states.add("New Jersey"); + states.add("Washington"); + + System.out.println("The states list: \n"+ states); + + // sublist the states list from 1 to 3 index + List statesSubList = states.subList(1, 3); + + System.out.println("\nThe states sublist from index 1 (inclusive) to 3 (exclusive): \n"+ statesSubList); + } +} diff --git a/collections/arraylist/sublist-method-in-arraylist/SubListMethodExceptionExample1.java b/collections/arraylist/sublist-method-in-arraylist/SubListMethodExceptionExample1.java new file mode 100644 index 0000000..7b9bbe3 --- /dev/null +++ b/collections/arraylist/sublist-method-in-arraylist/SubListMethodExceptionExample1.java @@ -0,0 +1,32 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; +import java.util.List; + +/** + * A java program to explain the subList() methods + * IndexOutOfBoundsException exception case. + * + * @author Gaurav Kukade at coderolls.com + */ +public class SubListMethodExceptionExample1 { + + public static void main(String[] args) { + // create an empty arraylist object 'states' + List states = new ArrayList(); + + // add state in the arraylist + states.add("California"); + states.add("Texas"); + states.add("Florida"); + states.add("New Jersey"); + states.add("Washington"); + + System.out.println("The states list: \n"+ states); + + // will throw IndexOutOfBoundsException + List statesSubList = states.subList(1, 7); + + System.out.println("\nThe states sublist from index 1 (inclusive) to 3 (exclusive): \n"+ statesSubList); + } +} diff --git a/collections/arraylist/sublist-method-in-arraylist/SubListMethodExceptionExample2.java b/collections/arraylist/sublist-method-in-arraylist/SubListMethodExceptionExample2.java new file mode 100644 index 0000000..b134bc6 --- /dev/null +++ b/collections/arraylist/sublist-method-in-arraylist/SubListMethodExceptionExample2.java @@ -0,0 +1,32 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; +import java.util.List; + +/** + * A java program to explain the subList() methods + * IllegalArgumentException exception case. + * + * @author Gaurav Kukade at coderolls.com + */ +public class SubListMethodExceptionExample2 { + + public static void main(String[] args) { + // create an empty arraylist object 'states' + List states = new ArrayList(); + + // add state in the arraylist + states.add("California"); + states.add("Texas"); + states.add("Florida"); + states.add("New Jersey"); + states.add("Washington"); + + System.out.println("The states list: \n"+ states); + + // will throw IllegalArgumentException + List statesSubList = states.subList(3, 1); + + System.out.println("\nThe states sublist from index 1 (inclusive) to 3 (exclusive): \n"+ statesSubList); + } +} diff --git a/collections/linkedlist/README.md b/collections/linkedlist/README.md new file mode 100644 index 0000000..c2945f3 --- /dev/null +++ b/collections/linkedlist/README.md @@ -0,0 +1,9 @@ +# Java Collections - LinkedList in Java + +This module contains articles related to LinkedList in Java. + +## Related articles + +- [LinkedList In Java](https://coderolls.com/linkedlist-in-java/) + +Visit [coderolls](https://coderolls.com/) to read more tutorials. diff --git a/collections/linkedlist/add-element-in-linkedlist/LinkedListAddExample.java b/collections/linkedlist/add-element-in-linkedlist/LinkedListAddExample.java new file mode 100644 index 0000000..13ce6f9 --- /dev/null +++ b/collections/linkedlist/add-element-in-linkedlist/LinkedListAddExample.java @@ -0,0 +1,32 @@ +package com.gaurav.ExProject.LinkedList; + +import java.util.LinkedList; + +/** + * A Java program to add an element to the LinkedList. + * + * The add(E e) method will add an element to + * the end of the linkedList. + * + * @author coderolls.com + * + */ +public class LinkedListAddExample { + + public static void main(String[] args) { + + LinkedList linkedList = new LinkedList(); + + //adding elements to the linkedList + linkedList.add("John"); + linkedList.add("Peter"); + + System.out.println(linkedList);// [John, Peter] + + // adding an element to the linkedList + // element will be added to the end of the linkedList + linkedList.add("Noah"); + + System.out.println(linkedList); // [John, Peter, Noah] + } +} diff --git a/collections/linkedlist/add-element-in-linkedlist/LinkedListAddExample2.java b/collections/linkedlist/add-element-in-linkedlist/LinkedListAddExample2.java new file mode 100644 index 0000000..978faad --- /dev/null +++ b/collections/linkedlist/add-element-in-linkedlist/LinkedListAddExample2.java @@ -0,0 +1,33 @@ +package com.gaurav.ExProject.LinkedList; + +import java.util.LinkedList; + +/** + * A Java program to add an element to the linkedlist + * at the specific index. + * + * The add(int index, E element) method will add + * an element at the specified index in LinkedList. + * + * @author coderolls.com + * + */ +public class LinkedListAddExample2 { + + public static void main(String[] args) { + + LinkedList linkedList = new LinkedList(); + + //adding elements to the linkedList using normal add method + linkedList.add("John"); + linkedList.add("Peter"); + linkedList.add("Karan"); + + System.out.println(linkedList);// [John, Peter, Karan] + + // adding an element to the LinkedList at index 1 + linkedList.add(1, "Noah"); + + System.out.println(linkedList); // [John, Noah, Peter, Karan] + } +} \ No newline at end of file diff --git a/collections/linkedlist/check-if-linkedlist-contains-an-element/LinkedListContains.java b/collections/linkedlist/check-if-linkedlist-contains-an-element/LinkedListContains.java new file mode 100644 index 0000000..4fb2e0b --- /dev/null +++ b/collections/linkedlist/check-if-linkedlist-contains-an-element/LinkedListContains.java @@ -0,0 +1,40 @@ +package com.gaurav.ExProject.LinkedList; + +import java.util.LinkedList; + +/** + * A Java program to check if the element is present + * in the linkedList using the contains(Object o) method. + * + * @author coderolls.com + * + */ +public class LinkedListContains { + + public static void main(String[] args) { + + LinkedList linkedList = new LinkedList(); + + linkedList.add("Uber"); + linkedList.add("Ola"); + linkedList.add("Didi"); + linkedList.add("Lyft"); + linkedList.add("Yandex"); + + System.out.println("LinkedList is as follows: \n"+ linkedList); + + + // checks if the linkedList contains "Ola" + // returns true if present + boolean isOlaPresnet = linkedList.contains("Ola"); // true + + System.out.println("\nCheck if linkedList contains Ola: "+ isOlaPresnet); + + // checks if the linkedList contains "Grab" + // returns true if present + boolean isGrabPresnet = linkedList.contains("Grab"); // false + + System.out.println("\nCheck if linkedList contains Grab: "+ isGrabPresnet); + + } +} diff --git a/collections/linkedlist/convert-linkedlist-to-array/LinkedListToArray.java b/collections/linkedlist/convert-linkedlist-to-array/LinkedListToArray.java new file mode 100644 index 0000000..e3d4365 --- /dev/null +++ b/collections/linkedlist/convert-linkedlist-to-array/LinkedListToArray.java @@ -0,0 +1,36 @@ +package com.gaurav.ExProject.LinkedList; + +import java.util.LinkedList; + +/** + * A java program to convert linkedlist to an array + * using the toArray() method. + * + * @author coderolls.com + * + */ +public class LinkedListToArray { + + public static void main(String[] args) { + + LinkedList linkedList = new LinkedList(); + linkedList.add("Walmart"); + linkedList.add("Amazon"); + linkedList.add("Apple"); + linkedList.add("Microsoft"); + linkedList.add("Google"); + linkedList.add("Uber"); + linkedList.add("Tesla"); + + System.out.println("Printing the linkedList: "); + System.out.println(linkedList); + + // convert linkedList to Object[] + Object[] arr = linkedList.toArray(); + + System.out.println("\nPrinting the object array elements: "); + for(Object obj:arr) { + System.out.println(obj.toString()); + } + } +} diff --git a/collections/linkedlist/convert-linkedlist-to-array/LinkedListToArray2.java b/collections/linkedlist/convert-linkedlist-to-array/LinkedListToArray2.java new file mode 100644 index 0000000..12203c4 --- /dev/null +++ b/collections/linkedlist/convert-linkedlist-to-array/LinkedListToArray2.java @@ -0,0 +1,36 @@ +package com.gaurav.ExProject.LinkedList; + +import java.util.LinkedList; + +/** + * A java program to convert linkedlist to an array + * using the toArray(T[] a) method. + * + * @author coderolls.com + * + */ +public class LinkedListToArray2 { + + public static void main(String[] args) { + + LinkedList linkedList = new LinkedList(); + linkedList.add("Walmart"); + linkedList.add("Amazon"); + linkedList.add("Apple"); + linkedList.add("Microsoft"); + linkedList.add("Google"); + linkedList.add("Uber"); + linkedList.add("Tesla"); + + System.out.println("Printing the linkedList: "); + System.out.println(linkedList); + + // convert linkedList to String array + String[] arr = linkedList.toArray(new String[linkedList.size()]); + + System.out.println("\nPrinting the String array elements: "); + for(String str:arr) { + System.out.println(str); + } + } +} diff --git a/collections/linkedlist/get-an-element-from-linkedlist/LinkedListGetElement.java b/collections/linkedlist/get-an-element-from-linkedlist/LinkedListGetElement.java new file mode 100644 index 0000000..62fe1b9 --- /dev/null +++ b/collections/linkedlist/get-an-element-from-linkedlist/LinkedListGetElement.java @@ -0,0 +1,30 @@ +package com.gaurav.ExProject.LinkedList; + +import java.util.LinkedList; + +/** + * A Java program to get an element from + * the linkedlist by it's index. + * + * @author coderolls.com + */ +public class LinkedListGetElement { + + public static void main(String[] args) { + + LinkedList linkedList = new LinkedList(); + linkedList.add("Adidas"); + linkedList.add("Air"); + linkedList.add("Nike"); + linkedList.add("Puma"); + linkedList.add("Reebok"); + + System.out.println("LinkedList: "); + System.out.println(linkedList); + + // get element at index 3 + String element = linkedList.get(3); // Puma + + System.out.println("\nElement at index 3 is: "+ element); + } +} diff --git a/collections/linkedlist/get-an-element-from-linkedlist/LinkedListGetFirst.java b/collections/linkedlist/get-an-element-from-linkedlist/LinkedListGetFirst.java new file mode 100644 index 0000000..883797e --- /dev/null +++ b/collections/linkedlist/get-an-element-from-linkedlist/LinkedListGetFirst.java @@ -0,0 +1,30 @@ +package com.gaurav.ExProject.LinkedList; + +import java.util.LinkedList; + +/** + * A Java program to get the first element from + * the linkedlist using getFirst() method. + * + * @author coderolls.com + */ +public class LinkedListGetFirst { + + public static void main(String[] args) { + + LinkedList linkedList = new LinkedList(); + linkedList.add("Adidas"); + linkedList.add("Air"); + linkedList.add("Nike"); + linkedList.add("Puma"); + linkedList.add("Reebok"); + + System.out.println("LinkedList: "); + System.out.println(linkedList); + + // get first element + String element = linkedList.getFirst(); // Adidas + + System.out.println("\nFirst element of the linkedList is: "+ element); + } +} diff --git a/collections/linkedlist/get-an-element-from-linkedlist/LinkedListGetLast.java b/collections/linkedlist/get-an-element-from-linkedlist/LinkedListGetLast.java new file mode 100644 index 0000000..a72f44e --- /dev/null +++ b/collections/linkedlist/get-an-element-from-linkedlist/LinkedListGetLast.java @@ -0,0 +1,30 @@ +package com.gaurav.ExProject.LinkedList; + +import java.util.LinkedList; + +/** + * A Java program to get the last element of + * the linkedlist using getLast() method. + * + * @author coderolls.com + */ +public class LinkedListGetLast { + + public static void main(String[] args) { + + LinkedList linkedList = new LinkedList(); + linkedList.add("Adidas"); + linkedList.add("Air"); + linkedList.add("Nike"); + linkedList.add("Puma"); + linkedList.add("Reebok"); + + System.out.println("LinkedList: "); + System.out.println(linkedList); + + // get first element + String element = linkedList.getLast(); // Adidas + + System.out.println("\nLast element of the linkedList is: "+ element); + } +} diff --git a/collections/linkedlist/get-an-index-of-element-of-linkedlist/LinkedListIndexOf.java b/collections/linkedlist/get-an-index-of-element-of-linkedlist/LinkedListIndexOf.java new file mode 100644 index 0000000..aad7aaf --- /dev/null +++ b/collections/linkedlist/get-an-index-of-element-of-linkedlist/LinkedListIndexOf.java @@ -0,0 +1,43 @@ +package com.gaurav.ExProject.LinkedList; + +import java.util.LinkedList; + +/** + * A Java program to get the first index of the element from + * the linkedlist using indexOf(Object o) method. + * + * @author coderolls.com + */ +public class LinkedListIndexOf { + + public static void main(String[] args) { + + LinkedList linkedList = new LinkedList(); + linkedList.add("PepsiCo"); + linkedList.add("DrPepper"); + linkedList.add("GoldSpot"); + linkedList.add("GoldSpot"); + linkedList.add("CocaCola"); + linkedList.add("Moxie"); + linkedList.add("GoldSpot"); + linkedList.add("Moxie"); + + System.out.println("LinkedList: "); + System.out.println(linkedList); + + // get first index of GoldSpot + int index = linkedList.indexOf("DrPepper"); // 1 + + System.out.println("\nIndex of the DrPepper in linkedList is: "+ index); + + // get first index of GoldSpot + int indexGS = linkedList.indexOf("GoldSpot"); // 2 + + System.out.println("\nIndex of the GoldSpot in linkedList is: "+ indexGS); + + // get first index of Moxie + int indexMoxie = linkedList.indexOf("Moxie"); // 5 + + System.out.println("\nIndex of the Moxie in linkedList is: "+ indexMoxie); + } +} diff --git a/collections/linkedlist/get-an-index-of-element-of-linkedlist/LinkedListLastIndexOf.java b/collections/linkedlist/get-an-index-of-element-of-linkedlist/LinkedListLastIndexOf.java new file mode 100644 index 0000000..b15b3ff --- /dev/null +++ b/collections/linkedlist/get-an-index-of-element-of-linkedlist/LinkedListLastIndexOf.java @@ -0,0 +1,43 @@ +package com.gaurav.ExProject.LinkedList; + +import java.util.LinkedList; + +/** + * A Java program to get the last index of the element from + * the linkedlist using lastIndexOf(Object o) method. + * + * @author coderolls.com + */ +public class LinkedListLastIndexOf { + + public static void main(String[] args) { + + LinkedList linkedList = new LinkedList(); + linkedList.add("PepsiCo"); + linkedList.add("DrPepper"); + linkedList.add("GoldSpot"); + linkedList.add("GoldSpot"); + linkedList.add("CocaCola"); + linkedList.add("Moxie"); + linkedList.add("GoldSpot"); + linkedList.add("Moxie"); + + System.out.println("LinkedList: "); + System.out.println(linkedList); + + // get last index of GoldSpot + int index = linkedList.lastIndexOf("DrPepper"); // 1 + + System.out.println("\nLast index of the DrPepper in linkedList is: "+ index); + + // get last index of GoldSpot + int indexGS = linkedList.lastIndexOf("GoldSpot"); // 6 + + System.out.println("\nLast index of the GoldSpot in linkedList is: "+ indexGS); + + // get last index of Moxie + int indexMoxie = linkedList.lastIndexOf("Moxie"); // 7 + + System.out.println("\nLast index of the Moxie in linkedList is: "+ indexMoxie); + } +} diff --git a/collections/linkedlist/iterate-linkedlist-in-java/LinkedListForEachMethod.java b/collections/linkedlist/iterate-linkedlist-in-java/LinkedListForEachMethod.java new file mode 100644 index 0000000..f9889c4 --- /dev/null +++ b/collections/linkedlist/iterate-linkedlist-in-java/LinkedListForEachMethod.java @@ -0,0 +1,30 @@ +package com.gaurav.ExProject.LinkedList; + +import java.util.LinkedList; +import java.util.List; + +/** + * A java program to iterate over linkedList + * using the java 8 foreach method. + * + * @author coderolls.com + */ +public class LinkedListForEachMethod { + + public static void main(String[] args) { + + List linkedList = new LinkedList(); + + linkedList.add("Mango"); + linkedList.add("Banana"); + linkedList.add("Grapes"); + linkedList.add("Watermelon"); + linkedList.add("Apple"); + linkedList.add("Avocado"); + + System.out.println("Iterating through LinkedList using forEach method and lamda expression........\n"); + + // add lambda expression in the foreach method + linkedList.forEach(s -> System.out.println("Object form the LinkedList is " + s)); + } +} diff --git a/collections/linkedlist/iterate-linkedlist-in-java/LinkedListForLoop.java b/collections/linkedlist/iterate-linkedlist-in-java/LinkedListForLoop.java new file mode 100644 index 0000000..92428da --- /dev/null +++ b/collections/linkedlist/iterate-linkedlist-in-java/LinkedListForLoop.java @@ -0,0 +1,38 @@ +package com.gaurav.ExProject.LinkedList; + +import java.util.LinkedList; +import java.util.List; + +/** + * A java program to iterate over linkedList + * using the basic for loop. + * + * @author coderolls.com + * + */ +public class LinkedListForLoop { + + public static void main(String[] args) { + + List linkedList = new LinkedList(); + + linkedList.add("Mango"); + linkedList.add("Banana"); + linkedList.add("Grapes"); + linkedList.add("Watermelon"); + linkedList.add("Apple"); + linkedList.add("Avocado"); + + System.out.println("Iterating through LinkedList using the basic for loop!\n"); + + int len = linkedList.size(); + + // iterate over linkedList using basic for loop + for (int i = 0; i < len; i++) { + + // get String object from linkedList at index i + String str = linkedList.get(i); + System.out.println("Object form the LinkedList at " + i + " is " + str); + } + } +} diff --git a/collections/linkedlist/iterate-linkedlist-in-java/LinkedListForeachLoop.java b/collections/linkedlist/iterate-linkedlist-in-java/LinkedListForeachLoop.java new file mode 100644 index 0000000..cd4f7eb --- /dev/null +++ b/collections/linkedlist/iterate-linkedlist-in-java/LinkedListForeachLoop.java @@ -0,0 +1,33 @@ +package com.gaurav.ExProject.LinkedList; + +import java.util.LinkedList; +import java.util.List; + +/** + * A java program to iterate over linkedList + * using the foreach loop. + * + * @author coderolls.com + * + */ +public class LinkedListForeachLoop { + + public static void main(String[] args) { + + List linkedList = new LinkedList(); + + linkedList.add("Mango"); + linkedList.add("Banana"); + linkedList.add("Grapes"); + linkedList.add("Watermelon"); + linkedList.add("Apple"); + linkedList.add("Avocado"); + + System.out.println("Iterating through LinkedList using the foreach loop!\n"); + + // iterate over linkedList using foreach loop + for (String str: linkedList) { + System.out.println("Object form the LinkedList is "+str); + } + } +} diff --git a/collections/linkedlist/iterate-linkedlist-in-java/LinkedListIterator.java b/collections/linkedlist/iterate-linkedlist-in-java/LinkedListIterator.java new file mode 100644 index 0000000..163e27a --- /dev/null +++ b/collections/linkedlist/iterate-linkedlist-in-java/LinkedListIterator.java @@ -0,0 +1,37 @@ +package com.gaurav.ExProject.LinkedList; + +import java.util.Iterator; +import java.util.LinkedList; +import java.util.List; + +/** + * A java program to iterate through LinkedList using Iterator interface. + * + * @author coderolls.com + * + */ +public class LinkedListIterator { + + public static void main(String[] args) { + List linkedList = new LinkedList(); + + linkedList.add("Mango"); + linkedList.add("Banana"); + linkedList.add("Grapes"); + linkedList.add("Watermelon"); + linkedList.add("Apple"); + linkedList.add("Avocado"); + System.out.println("Iterating through LinkedList using Iterator interface........\n"); + + // getting iterator + Iterator iterator = linkedList.iterator(); + + // hasNext() returns true only if object is available at next call + while (iterator.hasNext()) { + + // next() returns obejct, we can cast it to reuqired type + String str = iterator.next(); + System.out.println("Object form the LinkedList is " + str); + } + } +} \ No newline at end of file diff --git a/collections/linkedlist/iterate-linkedlist-in-java/LinkedListWhileLoop.java b/collections/linkedlist/iterate-linkedlist-in-java/LinkedListWhileLoop.java new file mode 100644 index 0000000..3293863 --- /dev/null +++ b/collections/linkedlist/iterate-linkedlist-in-java/LinkedListWhileLoop.java @@ -0,0 +1,44 @@ +package com.gaurav.ExProject.LinkedList; + +import java.util.LinkedList; +import java.util.List; + +/** + * A java program to iterate over linkedList + * using the while loop. + * + * @author coderolls.com + * + */ +public class LinkedListWhileLoop { + + public static void main(String[] args) { + + List linkedList = new LinkedList(); + + linkedList.add("Mango"); + linkedList.add("Banana"); + linkedList.add("Grapes"); + linkedList.add("Watermelon"); + linkedList.add("Apple"); + linkedList.add("Avocado"); + + System.out.println("Iterating through LinkedList using the while loop!\n"); + + int len = linkedList.size(); + + // iterate over linkedList using while loop + int i =0; + + while(i linkedList = new LinkedList(); + linkedList.add("Austin"); + linkedList.add("Boston"); + linkedList.add("Atlanta"); + linkedList.add("Madison"); + linkedList.add("Columbia"); + + System.out.println(linkedList); + + // add element at the beginning + linkedList.addFirst("Albany"); + System.out.println(linkedList); + + } + +} diff --git a/collections/linkedlist/linkedlist-addlast-method/LinkedListAddLast.java b/collections/linkedlist/linkedlist-addlast-method/LinkedListAddLast.java new file mode 100644 index 0000000..30fec6f --- /dev/null +++ b/collections/linkedlist/linkedlist-addlast-method/LinkedListAddLast.java @@ -0,0 +1,24 @@ +package com.gaurav.ExProject.LinkedList; + +import java.util.LinkedList; + +public class LinkedListAddLast { + + public static void main(String[] args) { + + LinkedList linkedList = new LinkedList(); + linkedList.add("Austin"); + linkedList.add("Boston"); + linkedList.add("Atlanta"); + linkedList.add("Madison"); + linkedList.add("Columbia"); + + System.out.println(linkedList); + + // add element at the end + linkedList.addLast("Albany"); + System.out.println(linkedList); + + } + +} diff --git a/collections/linkedlist/linkedlist-in-java/LinkedAllowDuplicates.java b/collections/linkedlist/linkedlist-in-java/LinkedAllowDuplicates.java new file mode 100644 index 0000000..03b62bb --- /dev/null +++ b/collections/linkedlist/linkedlist-in-java/LinkedAllowDuplicates.java @@ -0,0 +1,25 @@ +package com.gaurav.ExProject.LinkedList; + +import java.util.LinkedList; +/** + * A Java program to prove that LinkedList Allows null values + * @author coderolls.com + * + */ +public class LinkedAllowDuplicates { + + public static void main(String[] args) { + + LinkedList linkedList = new LinkedList(); + linkedList.add("John"); + linkedList.add(null); + linkedList.add("Mark"); + linkedList.add(null); + linkedList.add("Ruby"); + linkedList.add("Lucy"); + linkedList.add("Vikram"); + linkedList.add(null); + + System.out.println(linkedList); + } +} diff --git a/collections/linkedlist/linkedlist-in-java/LinkedAllowNull.java b/collections/linkedlist/linkedlist-in-java/LinkedAllowNull.java new file mode 100644 index 0000000..a26f0dd --- /dev/null +++ b/collections/linkedlist/linkedlist-in-java/LinkedAllowNull.java @@ -0,0 +1,25 @@ +package com.gaurav.ExProject.LinkedList; + +import java.util.LinkedList; +/** + * A Java program to prove that LinkedList Allows Duplicates + * @author coderolls.com + * + */ +public class LinkedAllowNull { + + public static void main(String[] args) { + + LinkedList linkedList = new LinkedList(); + linkedList.add("John"); + linkedList.add("Mark"); + linkedList.add("Mark"); + linkedList.add("Mark"); + linkedList.add("Ruby"); + linkedList.add("Lucy"); + linkedList.add("Vikram"); + linkedList.add("Vikram"); + + System.out.println(linkedList); + } +} diff --git a/collections/linkedlist/linkedlist-in-java/LinkedListInsertionOrder.java b/collections/linkedlist/linkedlist-in-java/LinkedListInsertionOrder.java new file mode 100644 index 0000000..14007ae --- /dev/null +++ b/collections/linkedlist/linkedlist-in-java/LinkedListInsertionOrder.java @@ -0,0 +1,22 @@ +package com.gaurav.ExProject.LinkedList; + +import java.util.LinkedList; +/** + * A Java program to prove that LinkedList maintains insertion order + * @author coderolls.com + * + */ +public class LinkedListInsertionOrder { + + public static void main(String[] args) { + + LinkedList linkedList = new LinkedList(); + linkedList.add("John"); + linkedList.add("Mark"); + linkedList.add("Ruby"); + linkedList.add("Lucy"); + linkedList.add("Vikram"); + + System.out.println(linkedList); + } +} diff --git a/collections/linkedlist/linkedlist-listiterator/LinkedListListIteratorExample.java b/collections/linkedlist/linkedlist-listiterator/LinkedListListIteratorExample.java new file mode 100644 index 0000000..7216f99 --- /dev/null +++ b/collections/linkedlist/linkedlist-listiterator/LinkedListListIteratorExample.java @@ -0,0 +1,36 @@ +package com.gaurav.ExProject.LinkedList; + +import java.util.LinkedList; +import java.util.ListIterator; +/** + * An example java program about the listIterator(int index) + * method of the linkedList. + * + * @author coderolls.com + */ +public class LinkedListListIteratorExample { + + public static void main(String[] args) { + + LinkedList states = new LinkedList<>(); + + // add state in the linkedList + states.add("California"); + states.add("Texas"); + states.add("Montana"); + states.add("Arizona"); + states.add("Florida"); + states.add("Michigan"); + states.add("New Jersey"); + states.add("Washington"); + states.add("Ohio"); + + //given index 3, iterator start from element with index 3 + ListIterator itr = states.listIterator(3); + System.out.println("Iterating the list from index 3\n"); + while(itr.hasNext()) { + String state = itr.next(); + System.out.println("The state :"+ state); + } + } +} \ No newline at end of file diff --git a/collections/linkedlist/linkedlist-listiterator/LinkedListListIteratorException.java b/collections/linkedlist/linkedlist-listiterator/LinkedListListIteratorException.java new file mode 100644 index 0000000..4eeb2ad --- /dev/null +++ b/collections/linkedlist/linkedlist-listiterator/LinkedListListIteratorException.java @@ -0,0 +1,36 @@ +package com.gaurav.ExProject.LinkedList; + +import java.util.LinkedList; +import java.util.ListIterator; +/** + * An example java program about the listIterator() + * method of the linkedList. + * + * @author coderolls.com + */ +public class LinkedListListIteratorException { + + public static void main(String[] args) { + + LinkedList states = new LinkedList<>(); + + // add state in the linkedList + states.add("California"); + states.add("Texas"); + states.add("Montana"); + states.add("Arizona"); + states.add("Florida"); + states.add("Michigan"); + states.add("New Jersey"); + states.add("Washington"); + states.add("Ohio"); + + //given index 120, it will throw IndexOutOfBoundsException + ListIterator itr = states.listIterator(120); + + while(itr.hasNext()) { + String state = itr.next(); + System.out.println("The state :"+ state); + } + } +} \ No newline at end of file diff --git a/collections/linkedlist/remove-element-from-linkedlist/LinkedListRemove.java b/collections/linkedlist/remove-element-from-linkedlist/LinkedListRemove.java new file mode 100644 index 0000000..4c3e3a2 --- /dev/null +++ b/collections/linkedlist/remove-element-from-linkedlist/LinkedListRemove.java @@ -0,0 +1,33 @@ +package com.gaurav.ExProject.LinkedList; + +import java.util.LinkedList; + +/** + * A Java program to remove head element from + * the linkedList using the remove() method. + * + * @author coderolls.com + * + */ +public class LinkedListRemove { + + public static void main(String[] args) { + + LinkedList linkedList = new LinkedList(); + + linkedList.add("BHIM"); + linkedList.add("PayTM"); + linkedList.add("Freecharge"); + linkedList.add("PhonePe"); + linkedList.add("JioPay"); + + System.out.println("LinkedList before removing an element:"); + System.out.println(linkedList); + + // removes head(first element) i.e. removes BHIM + linkedList.remove(); + + System.out.println("\nLinkedList after removing an element using remove() method:"); + System.out.println(linkedList); + } +} diff --git a/collections/linkedlist/remove-element-from-linkedlist/LinkedListRemoveFirst.java b/collections/linkedlist/remove-element-from-linkedlist/LinkedListRemoveFirst.java new file mode 100644 index 0000000..116fbff --- /dev/null +++ b/collections/linkedlist/remove-element-from-linkedlist/LinkedListRemoveFirst.java @@ -0,0 +1,33 @@ +package com.gaurav.ExProject.LinkedList; + +import java.util.LinkedList; + +/** + * A Java program to remove first element from + * the linkedList using the removeFirst() method. + * + * @author coderolls.com + * + */ +public class LinkedListRemoveFirst { + + public static void main(String[] args) { + + LinkedList linkedList = new LinkedList(); + + linkedList.add("BHIM"); + linkedList.add("PayTM"); + linkedList.add("Freecharge"); + linkedList.add("PhonePe"); + linkedList.add("JioPay"); + + System.out.println("LinkedList before removing an element:"); + System.out.println(linkedList); + + // removes first element i.e. removes BHIM + linkedList.removeFirst(); + + System.out.println("\nLinkedList after removing an element using removeFirst() method:"); + System.out.println(linkedList); + } +} diff --git a/collections/linkedlist/remove-element-from-linkedlist/LinkedListRemoveLast.java b/collections/linkedlist/remove-element-from-linkedlist/LinkedListRemoveLast.java new file mode 100644 index 0000000..048b98a --- /dev/null +++ b/collections/linkedlist/remove-element-from-linkedlist/LinkedListRemoveLast.java @@ -0,0 +1,33 @@ +package com.gaurav.ExProject.LinkedList; + +import java.util.LinkedList; + +/** + * A Java program to remove last element from + * the linkedList using the removeLast() method. + * + * @author coderolls.com + * + */ +public class LinkedListRemoveLast { + + public static void main(String[] args) { + + LinkedList linkedList = new LinkedList(); + + linkedList.add("BHIM"); + linkedList.add("PayTM"); + linkedList.add("Freecharge"); + linkedList.add("PhonePe"); + linkedList.add("JioPay"); + + System.out.println("LinkedList before removing an element:"); + System.out.println(linkedList); + + // removes first element i.e. removes BHIM + linkedList.removeLast(); + + System.out.println("\nLinkedList after removing an element using removeLast() method:"); + System.out.println(linkedList); + } +} diff --git a/collections/linkedlist/remove-element-from-linkedlist/LinkedListRemoveObject.java b/collections/linkedlist/remove-element-from-linkedlist/LinkedListRemoveObject.java new file mode 100644 index 0000000..53ac935 --- /dev/null +++ b/collections/linkedlist/remove-element-from-linkedlist/LinkedListRemoveObject.java @@ -0,0 +1,33 @@ +package com.gaurav.ExProject.LinkedList; + +import java.util.LinkedList; + +/** + * A Java program to remove the specified element from + * the linkedList using the remove(Object o) method. + * + * @author coderolls.com + * + */ +public class LinkedListRemoveObject { + + public static void main(String[] args) { + + LinkedList linkedList = new LinkedList(); + + linkedList.add("BHIM"); + linkedList.add("PayTM"); + linkedList.add("Freecharge"); + linkedList.add("PhonePe"); + linkedList.add("JioPay"); + + System.out.println("LinkedList before removing an element:"); + System.out.println(linkedList); + + // removes the specified element i.e. removes Freecharge + linkedList.remove("Freecharge"); + + System.out.println("\nLinkedList after removing an element using remove(Object o) method:"); + System.out.println(linkedList); + } +} diff --git a/collections/linkedlist/remove-element-from-linkedlist/LinkedListRemoveObjectByIndex.java b/collections/linkedlist/remove-element-from-linkedlist/LinkedListRemoveObjectByIndex.java new file mode 100644 index 0000000..23da316 --- /dev/null +++ b/collections/linkedlist/remove-element-from-linkedlist/LinkedListRemoveObjectByIndex.java @@ -0,0 +1,32 @@ +package com.gaurav.ExProject.LinkedList; + +import java.util.LinkedList; + +/** + * A Java program to remove element at the specified position i.e. index + * from the linkedList using the remove(int index) method. + * + * @author coderolls.com + */ +public class LinkedListRemoveObjectByIndex { + + public static void main(String[] args) { + + LinkedList linkedList = new LinkedList(); + + linkedList.add("BHIM"); + linkedList.add("PayTM"); + linkedList.add("Freecharge"); + linkedList.add("PhonePe"); + linkedList.add("JioPay"); + + System.out.println("LinkedList before removing an element:"); + System.out.println(linkedList); + + // removes the element at index 3 i.e. removes PhonePe + linkedList.remove(3); + + System.out.println("\nLinkedList after removing an element using remove(int index) method:"); + System.out.println(linkedList); + } +} diff --git a/collections/linkedlist/set-element-at-an-index-in-linkedlist/LinkedListSet.java b/collections/linkedlist/set-element-at-an-index-in-linkedlist/LinkedListSet.java new file mode 100644 index 0000000..251898b --- /dev/null +++ b/collections/linkedlist/set-element-at-an-index-in-linkedlist/LinkedListSet.java @@ -0,0 +1,36 @@ +package com.gaurav.ExProject.LinkedList; + +import java.util.LinkedList; + +/** + * A java program to set an element at specified index + * using the set(int index, E element) method. + * + * @author coderolls.com + */ +public class LinkedListSet { + + public static void main(String[] args) { + LinkedList linkedList = new LinkedList(); + + linkedList.add("IN"); + linkedList.add("US"); + linkedList.add("FR"); + linkedList.add("JP"); + linkedList.add("CN"); + linkedList.add("RU"); + + System.out.println("LinkedList before setting an element at index 4:"); + System.out.println(linkedList); + + // replaces CN with BR + // returns the previously present element at index 4 i.e CN + String previousElement = linkedList.set(4, "BR"); + + System.out.println("\nLinkedList after setting an element BR at index 4:"); + System.out.println(linkedList); + + System.out.println("\nPreviously present element at index 4:"); + System.out.println(previousElement); + } +} diff --git a/java-basic/for-each-loop/ArrayForEachExample.java b/java-basic/for-each-loop/ArrayForEachExample.java new file mode 100644 index 0000000..8ab7142 --- /dev/null +++ b/java-basic/for-each-loop/ArrayForEachExample.java @@ -0,0 +1,23 @@ +package com.gaurav.ExProject.ArrayList; + +/** + * A java program to traverse the array using the + * for-each loop i.e. enhanced for loop + * + * @author Guarav Kukade at coderolls.com + * + */ +public class ArrayForEachExample { + + public static void main(String[] args) { + + // create an array of marks + int[] numbers = { 88, 95, 65, 76, 78, 45, 95, 96, 56}; + + // traversing the array using for-each loop + for(int number: numbers) { + + System.out.println("The number is "+ number); + } + } +} diff --git a/java-basic/for-each-loop/ArrayListForEachExample.java b/java-basic/for-each-loop/ArrayListForEachExample.java new file mode 100644 index 0000000..01daa0d --- /dev/null +++ b/java-basic/for-each-loop/ArrayListForEachExample.java @@ -0,0 +1,36 @@ +package com.gaurav.ExProject.ArrayList; + +import java.util.ArrayList; +import java.util.List; + +/** + * A java program to traverse the collection using + * the for-each loop i.e. enhanced for loop + * + * @author Gaurav Kukade at coderolls.com + * + */ +public class ArrayListForEachExample { + + public static void main(String[] args) { + + // create an empty arraylist of Integer + List numbers = new ArrayList(); + + //add number to the list + numbers.add(1); + numbers.add(8); + numbers.add(8); + numbers.add(5); + numbers.add(4); + numbers.add(6); + numbers.add(3); + numbers.add(2); + numbers.add(9); + + //traversing the collection using for-each loop + for(Integer number: numbers) { + System.out.println("The number is "+ number); + } + } +} diff --git a/java-programs/largest-element-in-an-array/LargestElementInArray.java b/java-programs/largest-element-in-an-array/LargestElementInArray.java new file mode 100644 index 0000000..a4bb4d9 --- /dev/null +++ b/java-programs/largest-element-in-an-array/LargestElementInArray.java @@ -0,0 +1,32 @@ +package com.coderolls.JavaPrograms; +/** + * A Java program to find the largest number in an array + * using for loop iteration. + * + * @author coderolls.com + * + */ +public class LargestElementInArray { + + public static void main(String[] args) { + int[] arr = {2, 5, 9, 8, 11}; + + int largestElement = getLargest(arr); + System.out.println("Largest element in an array 'arr' is :"+ largestElement); + + } + + private static int getLargest(int[] arr) { + int n = arr.length; + int largest = arr[0]; + + for(int i=0; iarr[0]) { + largest = arr[i]; + } + } + return largest; + } +} diff --git a/java-programs/largest-element-in-an-array/LargestElementInArrayUsingArrays.java b/java-programs/largest-element-in-an-array/LargestElementInArrayUsingArrays.java new file mode 100644 index 0000000..d061699 --- /dev/null +++ b/java-programs/largest-element-in-an-array/LargestElementInArrayUsingArrays.java @@ -0,0 +1,28 @@ +package com.coderolls.JavaPrograms; + +import java.util.Arrays; + +/** + * A Java program to find the largest number in an array + * using Arrays.sort(). + * + * Arrays.sort() sort the array in natural sorting order + * + * @author coderolls.com + * + */ +public class LargestElementInArrayUsingArrays { + + public static void main(String[] args) { + int[] arr = {2, 5, 9, 8, 11}; + + int largestElement = getLargest(arr); + System.out.println("Largest element in an array 'arr' " + + "using Array.sort() is :"+ largestElement); + } + + private static int getLargest(int[] arr) { + Arrays.sort(arr); + return arr[arr.length-1]; + } +} diff --git a/java-programs/largest-element-in-an-array/LargestElementInArrayUsingStream.java b/java-programs/largest-element-in-an-array/LargestElementInArrayUsingStream.java new file mode 100644 index 0000000..311ee0d --- /dev/null +++ b/java-programs/largest-element-in-an-array/LargestElementInArrayUsingStream.java @@ -0,0 +1,27 @@ +package com.coderolls.JavaPrograms; + +import java.util.Arrays; +/** + * A Java program to find the largest number in an array + * using Java 8 Streams API. + * + * max() returns the maximum element of this stream + * + * @author coderolls.com + * + */ +public class LargestElementInArrayUsingStream { + + public static void main(String[] args) { + int[] arr = {2, 5, 9, 8, 11}; + + int largestElement = getLargest(arr); + System.out.println("Largest element in an array 'arr'" + + "using Java 8 Streams API is :"+ largestElement); + } + + private static int getLargest(int[] arr) { + int largest = Arrays.stream(arr).max().getAsInt(); + return largest; + } +} diff --git a/java-programs/second-largest-element-in-an-array/SecondLargestElementInArray.java b/java-programs/second-largest-element-in-an-array/SecondLargestElementInArray.java new file mode 100644 index 0000000..170298a --- /dev/null +++ b/java-programs/second-largest-element-in-an-array/SecondLargestElementInArray.java @@ -0,0 +1,41 @@ +package com.coderolls.JavaPrograms.second_largest; +/** + * A Java program to find the second largest number in an array + * by iterating over an array using for loop. + * + * @author coderolls.com + */ +public class SecondLargestElementInArray { + + public static void main(String[] args) { + int[] arr = {2, 5, 9, 8, 11, 18, 13}; + + int secondLargest = getSecondLargest(arr); + System.out.println("The second largest element in " + + "an array 'arr'is :"+ secondLargest); + } + + private static int getSecondLargest(int[] arr) { + int n =arr.length; + int largest =arr[0]; + int secondLargest = -1; + + for(int i=0; ilargest) { + //if you found the new largest, + //copy current largest to second largest and + //copy current element arr[i] to largest + secondLargest = largest; + largest = arr[i]; + }else if(arr[i]!=largest) { + // if the current element arr[i] is not the largest and + // still larger than the current secondLargest + // then copy it to secondLargest + if(arr[i]>secondLargest) { + secondLargest = arr[i]; + } + } + } + return secondLargest; + } +} diff --git a/java-programs/second-largest-element-in-an-array/SecondLargestElementInArrayUsingArrays.java b/java-programs/second-largest-element-in-an-array/SecondLargestElementInArrayUsingArrays.java new file mode 100644 index 0000000..5e3aa18 --- /dev/null +++ b/java-programs/second-largest-element-in-an-array/SecondLargestElementInArrayUsingArrays.java @@ -0,0 +1,26 @@ +package com.coderolls.JavaPrograms.second_largest; + +import java.util.Arrays; + +/** + * A Java program to find the second largest number in an array + * using Arrays.sort() method. + * + * @author coderolls.com + */ +public class SecondLargestElementInArrayUsingArrays { + + public static void main(String[] args) { + int[] arr = {2, 5, 9, 8, 11, 18, 13}; + + int secondLargest = getSecondLargest(arr); + System.out.println("The second largest element in" + + "an array 'arr' is using Arrays.sort() :"+ secondLargest); + } + + private static int getSecondLargest(int[] arr) { + Arrays.sort(arr); + // return second largest, so length-2 + return arr[arr.length-2]; + } +} diff --git a/java-string/java-reverse-string-using-recursion/ReverseStringUsingRecursion.java b/java-string/java-reverse-string-using-recursion/ReverseStringUsingRecursion.java new file mode 100644 index 0000000..77a8f21 --- /dev/null +++ b/java-string/java-reverse-string-using-recursion/ReverseStringUsingRecursion.java @@ -0,0 +1,23 @@ +package ArrayListAddExample; +/** + * A java program to reverse a striong using recursion. + * + * @author gaurav + * + */ +public class ReverseStringUsingRecursion { + + public static void main(String[] args) { + + String str = "Hello"; + System.out.println(reverse(str)); + + } + + public static String reverse(String str) { + if ((null == str) || (str.length() <= 1)) { + return str; + } + return reverse(str.substring(1)) + str.charAt(0); + } +}