C++ Queue empty() Function

C++ Queue empty() function is used for testing whether the container is empty or not. Sometimes before actually starting the work with the individual elements of the containers, it is more feasible to look up if the container is empty, so this function finds its usage in such cases.

Syntax

Parameters

There are no parameters. The function is only used to test for the emptiness of the container and hence takes no parameter.

Return value

If the container under reference is empty, then the method returns 'true' else returns 'false'.

Example 1

#include <iostream>
#include <queue>
int main()
{
	std::queue<int> newqueue;
	int result=0;
	for (int j=1; j<=10; j++)
	newqueue.push(j);
	while (!newqueue.empty () )
	{
		result += newqueue.front ();
		newqueue.pop();
	}
	std::cout << "result is: " << result;
	return 0;
}

Output:

result is: 55

Example 2

#include <iostream>
#include <queue>
using namespace std;
int main()
{
	queue<int> newqueue;
	newqueue.push(55);
	if(newqueue.empty())
	{
		cout<<"The queue is empty";
	}
	else
	{
		cout<<"The queue is not empty";
	}
	return 0;
}

Output: