• Source 
    1. /* Queue follows FIFO structure. It means First Input First Output */
    2.  
    3. #include<iostream>
    4. #include<queue>
    5. using namespace std;
    6.  
    7. int main()
    8. {
    9.  
    10.     int i=52;
    11.     queue<int> q;        // you can write double / string type queue also
    12.  
    13.     q.push(50);
    14.     q.push(62);
    15.     q.push(14);
    16.     q.pop();        // it will pop first number 50
    17.     q.push(i);
    18.  
    19.  
    20.     printf("The size of queue is now %d\n\n", q.size() );
    21.  
    22.     while( !q.empty() ){    // if not empty then continue
    23.         printf("-> %d\n", q.front()  );
    24.         q.pop();
    25.  
    26.     }
    27.     printf("\n\t\t*** Thanks ...\n");
    28.     getchar();
    29. return 0;
    30. }
    31.  
    32. /*
    33. In the same way, you can use Stack
    34.  
    35.  
    36. #inlcude<stack>
    37.  
    38.   // Declare:
    39.   stack<double> s;          // now, write your code . . .
    40.  
    41. // In same way you can use Priority queue
    42.     // Declare
    43.   priority_queue<int > q;   // now, write your code . . .
    44.  
    45. */
    46.