C++ Queue size function returns the number of queue elements. The number of elements in the queue is an actual representation of the size, and the size value is given by this function.
Syntax
Example
size_type size() const;
Parameters
The function does not take any parameter, and it just returns the queue size.
Return value
The number of elements in the queue is returned. In other words, the size of the queue is given.
Example 1
Example
#include <iostream>
#include <queue>
int main()
{
std::queue<int> newqueue;
std::cout<< "0. size: "<< newqueue.size();
for(int j=0; j<5; j++)
newqueue.push(j);
std::cout<<"\n";
std::cout << "1. size: " << newqueue.size();
newqueue.pop();
std::cout<<"\n";
std::cout << "2. size: "<< newqueue.size();
return 0;
}
Output:
Output
0.size: 0
1.size: 5
2.size: 4
Example 2
Example
#include <iostream>
#include <queue>
using namespace std;
int main()
{
int result = 0;
queue<int> newqueue;
newqueue.push(12);
newqueue.push(24);
newqueue.push(36);
newqueue.push(48);
cout<<"Size of the queue is ";
cout<<newqueue.size();
return 0;
}
Output:
Output
Size of queue is 4
Complexity
The complexity is constant.
Data races
The function accesses the container. By accessing the container the size of the queue is evaluates.
Exception Safety
Guarantee as equivalent to the operations that are performed on the underlying container object is provided.