C++ STL playground

closestK.cpp

#include <iostream>
#include <vector>
#include <map>
#include <queue>
#include <math.h>

using namespace std;

class Point
{
	public:
		Point() {};                                      // default constructor
		Point(int _x, int _y) { x = _x; y = _y; }        // constructor
		bool operator<(const Point&) const;              // overloaded < operator
		
		int get_x() const { return x; } 
		int get_y() const { return y; }
		
    private:
		int x, y;                                        //data fields
};

/* overload the less-than operator so priority queues know how to compare two Point objects */
bool Point::operator<(const Point& p) const
{
	return sqrt(pow(x,2)+pow(y,2)) > sqrt(pow(p.x,2)+pow(p.y,2));
}

int main(int argc, char *argv[]) {
    vector<Point> points;
 
    points.push_back(Point(6,2));

    points.push_back(Point(3,4));
	
    points.push_back(Point(1,1));
	
    points.push_back(Point(3,2));

    priority_queue<Point> pq;

    pq.push(points[0]);

    pq.push(points[1]);

    pq.push(points[2]);

    pq.push(points[3]);

    while (!pq.empty()) {
	cout << pq.top().get_x()  << " " << pq.top().get_y() << endl;         
        pq.pop();   
    }                                              
    return 0; 
}

Print K closest points from Origin on a cartesian plane