Classes and Objects in Dart

1. What is a Class?

A class in Dart is like a blueprint or model for creating objects .

Blueprint is also like a model .

It defines:

• What properties (variables/data) an object will have
• What methods (functions/behavior) the object can do

Example: If a house is an object, then a class is the house plan.

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Syntax of a Class in Dart:

class Person {
    String name = '';
    int age = 0;
    void sayHello() {
        print("Hello, my name is $name and I am $age years old.");
    }
}

Here:

• name and age are fields (variables)
• sayHello() is a method

2. What is an Object?

An object is a real-world instance of a class. It’s like building an actual house from the blueprint.

Creating an Object

void main() {
    Person p1 = Person();  // creating an object
    p1.name = "Sakif";
    p1.age = 23;
    p1.sayHello();  // Output: Hello, my name is Sakif and I am 23 years old.
}

Here:

• p1 is an object of the Person class
• You can access the object’s properties and methods using the dot (.) operator