C++ Programming - References

#include<iostream.h> 
int i, j; 
class IndiaBix
{
    public:
    IndiaBix(int x = 0, int y = 0)
    {
        i = x; 
        j = x; 
        Display();
    }
    void Display()
    {
        cout<< j <<" ";
    } 
}; 
int main()
{
    IndiaBix objBix(10, 20); 
    int &s = i; 
    int &z = j; 
    i++;
    cout<< s-- << " " << ++z; 
    return 0; 
}

#include<iostream.h> 
int x, y; 
class BixTest
{
    public:
    BixTest(int xx = 0, int yy = 0)
    {
        x = xx;
        y = yy;
        Display(); 
    } 
    void Display()
    {
        cout<< x << " " << y << " ";
    }
};
int main()
{
    BixTest objBT(10, 20); 
    int &rx = x; 
    int &ry = y; 
    ry = x;
    rx = y;
    cout<< rx--; 
    return 0; 
}

#include<iostream.h> 
class IndiaBix
{
    int a, b, c; 
    public:
    void SetValue(int x, int y ,int z)
    {
        a = x;
        b = y;
        c = z;
    } 
    void Display()
    {
        cout<< a << " " << b << " " << c;
    } 
}; 
int main()
{
    IndiaBix objBix;
    int x  = 2;
    int &y = x;
    y = 5;
    objBix.SetValue(x, ++y, x + y);
    objBix.Display();
    return 0; 
}

#include<iostream.h> 
class BixBase
{
    int x;
    public:
    BixBase(int xx = 0)
    {
        x = xx; 
    }
    void Display()
    {
        cout<< x ;
    }
};
class BixDerived : public BixBase
{
    int y; 
    public:
    BixDerived(int yy = 0)
    {
        y = yy;
    }
    void Display()
    {
        cout<< y ;
    }
};
int main()
{
    BixBase objBase(10); 
    BixBase &objRef = objBase;

    BixDerived objDev(20); 
    objRef = objDev;

    objDev.Display(); 
    return 0; 
}

#include<iostream.h> 
class IndiaBix
{
    int x, y; 
    public:
    IndiaBix(int xx = 0, int yy = 0)
    {
        x = xx; 
        y = yy;
    }
    void Display()
    {
        cout<< x << " " << y;
    }
    IndiaBix operator +(IndiaBix z)
    {
        IndiaBix objTemp;
        objTemp.x = x + z.x;
        objTemp.y = y + z.y;
        return objTemp; 
    }
};
int main()
{
    IndiaBix objBix1(90, 80); 
    IndiaBix objBix2(10, 20); 
    IndiaBix objSum; 
    IndiaBix &objRef = objSum; 
    objRef = objBix1 + objBix2; 
    objRef.Display(); 
    return 0; 
}