stl-priority_queue.cpp

/* STL queue and priority queue examples */

#include <iostream>
#include <queue>

using namespace std;

/* simple queue example */
void functionA()
{
  queue <int> q;                  //q is a queue of integers

  q.push(2);                      //put 2, 5, 3, 2 into the queue
  q.push(5);
  q.push(3);
  q.push(1);
  cout<<"q contains " << q.size() << " elements.\n";

  while (!q.empty()) {
    cout << q.front() << endl;    //print out the first element in the queue
    q.pop();                      //remove the first element of the queue
  }
}

/* simple priority queue example */
void functionB()
{
  priority_queue <int> pq;      //pq is a priority queue of integers

  pq.push(2);                   //put 2, 5, 3, 1 into the priority queue
  pq.push(5);
  pq.push(3);
  pq.push(1);
  cout<<"pq contains " << pq.size() << " elements.\n";

  while (!pq.empty()) {
    cout << pq.top() << endl;   //print out the highest priority element
    pq.pop();                   //remove the highest priority element
  }
}

int main()
{
  cout << "calling functionA...\n";
  functionA();
  cout << "calling functionB...\n";
  functionB();

  return 0;
}