Operator Overloading Basics (cpp): member function

// cpp: operator overloading( member function ), basics
// Author: fueanta

#include <iostream>
#include <conio.h>

using namespace std;

class point
{
   int x,y;
public:
    point(int x=0, int y=0):x(x),y(y) {}
    void show();
    // Operator Over-loadings:
    point operator-();
    point operator+(point);
    point operator+(int);
    void operator=(point);
    point operator+=(int);
    void operator+=(point);
    point operator++();
    point operator++(int);
    bool operator==(point);
};

void point::show()
{
    cout << "X= " << x << "\tY= " << y << endl;
}
point point::operator-()
{
    return point(-x,-y);
}
point point::operator+(point i)
{
    return point(x+i.x, y+i.y);
}
point point::operator+(int i)
{
    return point(x+i, y+i);
}
void point::operator=(point i)
{
    x=i.x; y=i.y;
    //return *this; then, return type should be given.
}
point point::operator+=(int i)
{
    x+=i; y+=i;
    return *this;
}
void point::operator+=(point i)
{
    x+= i.x; y+= i.y;
    //return *this; then, return type should be given.
}
point point::operator++()
{
    return point(++x, ++y);
}
point point::operator++(int)
{
    return point(x++, y++);
}
bool point::operator==(point i)
{
    if(x==i.x && y==i.y)
        return true;
    else
        return false;
}

int main()
{
    point p1(10,20),p2(20,30),p3;
    p3= -p1;
    p3.show();
    p3= p1+p2;
    p3.show();
    p3= p1+5;
    p3.show();
    p3= p2;
    p3.show();
    p3+= 5;
    p3.show();
    p1+= p2;
    p1.show();
    p3= ++p1;
    p3.show();
    p1.show();
    p3= p2++;
    p3.show();
    p2.show();
    //point p4(31,51);
    if (p1==p2)
        cout << "Equal." << endl;
    else
        cout << "Not Equal." << endl;
    getch();
    return 0;
}