std::queue size() method

since C++98

// Const version only
size_type size() const

Returns the number of elements in the underlying container, that is, c.size().

Parameters

(none)

Return value

The number of elements in the container.

Complexity

Constant - O(1).

Example

Main.cpp

#include <algorithm>
#include <iostream>
#include <queue>
 
int main()
{
    std::queue<int> container;
 
    std::cout << "Initially, container.size(): " << container.size() << '\n';
 
    for (int i = 0; i < 7; ++i)
        container.push(i);
 
    std::cout << "After adding elements, container.size(): " << container.size() << '\n';
}

Output

Initially, container.size(): 0
After adding elements, container.size(): 7