Which of the following statement is correct about the program given below?

#include<iostream.h> 
class AptitudeCrack
{
    int x, y; 
    public:
    AptitudeCrack(int xx = 0, int yy = 0)
    {
        x = xx; 
        y = yy;
    }
    void Display()
    {
        cout<< x << ' ' << y;
    }
    AptitudeCrack operator +(AptitudeCrack z)
    {
        AptitudeCrack objTemp;
        objTemp.x = x + z.x;
        objTemp.y = y + z.y;
        return objTemp; 
    }
};
int main()
{
    AptitudeCrack objAptitude1(90, 80); 
    AptitudeCrack objAptitude2(10, 20); 
    AptitudeCrack objSum; 
    AptitudeCrack &objRef = objSum; 
    objRef = objAptitude1 + objAptitude2; 
    objRef.Display(); 
    return 0; 
}