/**********************************************************************************
 *** FILE: deque_sample.cpp
 *** DATE: 02/09/2004
 *** AUTHOR: Daniel Dementiev
 *** GOAL: Illustrate how to create a simple priority queue of class pointers
 ***       using the deque container from STL.
 ***       Please notice several things:
 ***        - we need to define the < (less than) operator for the Robot class
 ***          to be able to compare robots by their priority
 ***        - we need to create a special class PRobot that contains nothing but
 ***          a pointer to a robot. This is done exclusively to be able to define
 ***          a comparison operator < (less than) for robot pointers.
 ***        - inside the PRobot class we also redefine the type conversion operator
 ***          Robot*() that allows us to conside any object of the PRobot class as
 ***          a simple pointer to an object of the class Robot.
 **********************************************************************************/
#include <iostream>
#include <deque>
#include <algorithm>
using namespace std;

class Robot{
   private:
      int priority;
   public:
      Robot() : priority(rand()%25+1) {};
      int getPr() { return priority; };
      friend bool operator<(const Robot &a, const Robot &b);
};

bool operator<(const Robot &a, const Robot &b)
{
   return a.priority > b.priority;
}


class PRobot {
   private:
      Robot *robot_pointer;
   public:
      PRobot() : robot_pointer(NULL) {};
      PRobot(Robot *robot) : robot_pointer(robot) {};
      operator Robot*() const { return robot_pointer; };
      friend bool operator<(const PRobot &a, const PRobot &b);
};

bool operator<(const PRobot &a, const PRobot &b)
{
   return *a.robot_pointer < *b.robot_pointer;
}



void main()
{
   int i, j;
   deque<PRobot> pq;
   Robot *tank;

   for(i=0;i<15;i++){
      tank = new Robot();
      pq.push_back(tank);
      cout<<"Inserted tank with priority "<<tank->getPr()<<" into the array\n";
   }

   sort(pq.begin(), pq.end());

   cout<<"\nAfter sorting teh array is:\n";
   while( ! pq.empty() ){
      tank = pq.front();
      cout<<tank->getPr()<<" ";
      pq.pop_front();
   }
}