// test_priority_queue.cpp   just demo some features, not a full test

#include <iostream>
#include <queue>
using namespace std;

typedef priority_queue<int> my_queue;
           // give my typename to a priority queue of integers
           // this simplifies code for function prototypes, etc.
                              
void put(const my_queue Q)  // function to output a priority queue
                            // of type my_queue (no iterator available)
{
  my_queue T = Q; // make a copy because we have to pop to get next highest priority
  cout << "Q(" << Q.size() << ")= ";  // use while loop to be safe 
  while(!T.empty())
  {
    cout << T.top() << " ";
    T.pop();
  }
  cout << endl;  
}

int main()
{
  my_queue Q;        // construct an empty queue
  
  cout << "test_priority_queue running, Q is "
       << (Q.empty() ? "empty" : "has junk") << endl;
  Q.push(3);
  Q.push(5);
  Q.push(1);
  Q.push(4);
  Q.push(2);  // push in any order, default comes out largest first

  cout << " initial    ";
  put(Q);     // size() and  top() demonstrated in 'put()'
  
  Q.pop();    // removes highest priority item (largest by default)
  Q.push(3);  // duplicates OK
  Q.push(3);
  cout << " added 3's  ";
  put(Q);
  
  return 0;
}
// Output of this program is:
// test_priority_queue running, Q is empty
//  initial    Q(5)= 5 4 3 2 1 
//  added 3's  Q(6)= 4 3 3 3 2 1