.front() c++
// queue::front
#include <iostream> // std::cout
#include <queue> // std::queue
int main ()
{
std::queue<int> myqueue;
myqueue.push(77);
myqueue.push(16);
cout << myqueue.front();
myqueue.front() -= myqueue.back(); // 77-16=61
std::cout << "myqueue.front() is now " << myqueue.front() << '\n';
return 0;
}