C++

#ifndef _POINT_H
#define _POINT_H

#include <iostream>

class Point {

private:

    /**
     * x coord
     */
    double x;

    /**
     * coord y
     */
    double y;

public:


    Point():x(0),y(0)
    {
    }

    Point(double x , double y);

    //copy constructor
    Point(const Point &p);

    ~Point();

    double getX();

    void setX(double _x);

    double getY();

    void setY(double _y);

    friend Point operator+(const Point &p1, const Point &p2);

    friend Point operator-(const Point &p1, const Point &p2);

    friend std::ostream &operator<<( std::ostream &output, const Point &p );


};
#endif

#include <iostream>
#include "Point.h"

using namespace std;

Point::Point(double _x, double _y)
{
    x = _x;
    y = _y;
}

Point::Point(const Point &p){
    x = p.x;
    y = p.y;
    cout << "copy constructor" << endl;
}

Point::~Point()
{
}

double Point::getX(){
    return x;
}

void Point::setX(double _x){
    x = _x;
}

double Point::getY(){
    return y;
}

void Point::setY(double _y){
    y = _y;
}

Point operator+(const Point &p1, const Point &p2)
{
    return Point(p1.x + p2.x, p1.y + p2.y);
}

Point operator-(const Point &p1, const Point &p2)
{
    return Point(p1.x - p2.x, p1.y - p2.y);
}

ostream& operator<<(ostream &output, const Point &p)
{
  output << "Point coords x: " << p.x << " y: " << p.y;
  return output;
}

/* test pass object to function */

void test_value(Point p)
{
    p.setY(100);
    cout << p << endl;
}

void test_pointer(Point * p)
{
    p->setY(1000);
}

void test_reference(Point & p)
{
    p.setY(200);
}

int main()
{
/* operator overload */
    cout << endl << "OPERATOR OVERLOAD" << endl << endl;
    Point test_add = p1 + p2;
    cout << test_add << endl;

    Point test_subtract = p1 - p2;
    cout << test_subtract << endl;

    cout << test_subtract << endl;

    Point copy = test_add;

    cout << test_add << endl;
    test_value(test_add);
    cout << test_add << endl;

    Point* pointer = &test_add;
    test_pointer(pointer);
    cout << test_add << endl;

    test_reference(test_add);
    cout << test_add << endl;

    return 0;
}