C++ Queue pop() Function

C++ Queue pop() function is used for removing the topmost element of the queue. The function is implied only for deletion of elements.

Syntax

Parameters

The function only performs the deletion operation and does not accept any parameters.

Return value

There is no return value for this function; it is only implied for deletion of elements.

Example 1

#include <iostream>
#include <queue>
int main()
{

		std::queue<int> newqueue;
		int qint;
		std::cout << "Enter some valid integer values(press 0 to end)";
		do
		{
			std::cin>> qint;
			newqueue.push(qint);
		}	while (qint);
	
		std::cout << "newqueue contains: ";
		while(!newqueue.empty())
		{
			std::cout <<" " <<newqueue.front();
			newqueue.pop();
		}
		return 0;
}

Output:

Enter some valid integer values(press 0 to end)
1 
3
4
5
6
7
0
newqueue contains: 1 3 4 5 6 7 0

Example 2

#include <iostream>
#include <queue>
using namespace std;
int main()
{
	{
		int a=0;
		queue<int> newqueue;
		newqueue.push(4);
		newqueue.push(8);
		newqueue.push(12);
		newqueue.push(16);
		while(!newqueue.empty())
		{
			newqueue.pop();
			a++;
		}
		cout<<a;
	}
}

Output:

Complexity

The complexity of the function is constant.

Data races

This function modifies the container and all of its elements. After the deletion of an element from the queue, respective positions of all the other elements are also modified.