/* --------------------------------------------------------------
   Queue:  FIFO data structure

   Methods	Description
   push()	inserts an element at the back of the queue
   pop()	removes an element from the front of the queue
   front()	returns the first element of the queue
   back()	returns the last element of the queue
   size()	returns the number of elements in the queue
   empty()	returns true if the queue is empty
   --------------------------------------------------------------- */

#include <iostream>
#include <queue>

using namespace std;

int main() {

  // create a queue of string
  queue<string> animals;

  // push elements into the queue
  animals.push("Cat");
  animals.push("Dog");
  
  cout << "Queue size = " << animals.size() << "\n\n";

  cout << "Queue: ";

  // print elements of queue
  // loop until queue is empty
  while(!animals.empty()) 
  {
    // print the element
    cout << animals.front() << ", ";

    // pop element from the queue
    animals.pop();
  }
  cout << endl;
 
  return 0;
}