Simple Operator Overloading

// operator-overloading.cpp : Defines the entry point for the Operator Overloading application.
//

#include <cstdlib>
#include <iostream>

using namespace std;
class Nums{
private:
	int x, y, z;
public:
	Nums(int p, int q, int r);
	Nums(); // This non-parameterized constructor is unneccessary here
	Nums operator+(const Nums& obj); // Operator "+" Signature
	Nums operator-(const Nums& obj); // Operator "-" Signature
	
    // Method that displays the value of all member variables
	void Display(string objName){
         cout << objName << " :: value of x = " << this->x << endl;
         cout << objName << " :: value of y = " << this->y << endl;
         cout << objName << " :: value of z = " << this->z << endl;        
    }
	
};

// Constructor 
Nums::Nums(int p, int q, int r){
	x = p;
	y = q;
	z = r;
}
// Default Constructor 
Nums::Nums(){
	x = y = z = 0;
}
// Operator "+" Definition
Nums Nums::operator+(const Nums& obj){
	int _x = x + obj.x;
	int _y = y + obj.y;
	int _z = y + obj.z;
	return Nums(_x, _y, _z);

}
// Operator "-" Definition
Nums Nums::operator-(const Nums& obj){
	int _x = x - obj.x;
	int _y = y - obj.y;
	int _z = z - obj.z;
	return Nums(_x, _y, _z);

}

int main(int argc, char *argv[])
{
	Nums a = Nums(1, 2, 3); // Initializing First Nums Object
	Nums b = Nums(4, 5, 6); // Initializing Second Nums Object
	Nums add = a + b; // Nums Object that Contains Addition Result.
	Nums sub = b - a; // Well, you know what this object contains.

 
    a.Display("First Object"); // Shows values of Object a
    b.Display("Second Object"); // Shows values of Object b
    
    add.Display("Addition Operation"); // Shows values after the addition of two objects
    sub.Display("Subtraction Operation"); // Shows values after the subtraction of two objects
    
    system("PAUSE");
    return EXIT_SUCCESS;
}