queue队列

A queue also provides two time operations: adding an element to the end of the queue, and removing the first element in the queue. It is only possible to access the first and last element of a queue.

queue<int> q;
q.push(3);
q.push(2);
q.push(5);
cout << q.front(); // 3
q.pop();
cout << q.front(); // 2