The list::pop_front() is a built-in function in C++ STL which is used to remove an element from the front of a list container. This function thus decreases the size of the container by 1 as it deletes the element from the front of the list.
Syntax
list_name.pop_front();
Parameters
- The function does not accept any parameter.
Return Value
- This function does not return anything.
Example
The below program illustrates the list::pop_front() function in C++ STL.
// CPP program to illustrate the
// list::pop_front() function
#include <bits/stdc++.h>
using namespace std;
int main()
{
// Creating a list
list<int> demoList;
// Adding elements to the list
// using push_back()
demoList.push_back(10);
demoList.push_back(20);
demoList.push_back(30);
demoList.push_back(40);
// Initial List:
cout << "Initial List: ";
for (auto itr = demoList.begin(); itr != demoList.end();
itr++)
cout << *itr << " ";
// removing an element from the front of List
// using pop_front
demoList.pop_front();
// List after removing element from front
cout << "\n\nList after removing an element from "
"front: ";
for (auto itr = demoList.begin(); itr != demoList.end();
itr++)
cout << *itr << " ";
return 0;
}
Output
Initial List: 10 20 30 40 List after removing an element from front: 20 30 40
Time Complexity: O(n)
Auxiliary Space: O(1)