// Using a priority_queue 
// Plus an example of using a function object 
// Ken Moore 2003

#pragma warning(disable : 4786) 
#include <iostream>
#include <queue>
#include <string>
#include <list>

using namespace std;

template<class T>
class plusk{
private:
	T sum;
public:
	plusk():sum(0){}
	void operator()(const T &a){
		sum+=a;
	}
	T getSum(){return sum;}
};

// function object comparator
template<class T>// templating is optional
struct comp{

	bool operator()(const T &a,const T &b)const{

		// least to greatest
		return b>a;

		// greatest to least
		// return b<a;
	}
};


void main()
{   
	/*
	    demonstrate the various manifestations of a
		priority_queue
	*/

	// use my own comparator function
	//priority_queue<int, vector<int>, comp<int> > pq;
	// reverse default order
	//priority_queue<int, deque<int>,greater<int> > pq;

	// uses the less function and gives reverse order
	priority_queue<int> pq;

	pq.push(987);
	pq.push(9);
	pq.push(98742);
	pq.push(98);

	while(!pq.empty())
	{
		cout << pq.top() << "\n";
		pq.pop();
	}

    // demonstrate the use of a funtion object
	vector<int> v;
	v.push_back(100);
	v.push_back(1);
	v.push_back(10000);
	v.push_back(10);

	//plusk<int> p = for_each(v.begin(),v.end(),plusk<int>());
	//cout << p.getSum() << endl;

	// equivalent to above 2 lines of code
	cout << for_each(v.begin(),v.end(),plusk<int>()).getSum() << endl;

	// without for_each ("for_each" is an STL algorithm)
	vector<int>::iterator it;
	plusk<int> pk;
	for(it = v.begin(); it != v.end(); it++)
		pk(*it);
	cout << pk.getSum() << endl;
}