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

#include<iostream.h> 
int main()
{
    int x = 10;
    int &y = x;
    x++;
    cout<< x << " " << y++;
    return 0; 
}

#include <iostream.h> 
enum xyz 
{
    a, b, c
}; 
int main()
{
    int x = a, y = b, z = c; 
    int &p = x, &q = y, &r = z; 
    p = z; 
    p = ++q;
    q = ++p;
    z = ++q + p++; 
    cout<< p << " " << q << " " << z;
    return 0; 
}

#include<iostream.h> 
int CuriousTabFunction(int m)
{
    m *= m;
    return((10)*(m /= m)); 
}
int main()
{
    int c = 9, *d = &c, e;
    int &z = e;
    e = CuriousTabFunction(c-- % 3? ++*d :(*d *= *d));
    z = z + e / 10;
    cout<< c << " " << e;
    return 0;
}

#include<iostream.h> 
int main()
{
    int x = 80; 
    int &y = x;
    x++;
    cout << x << " " << --y;
    return 0;
}

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

    CuriousTabDerived objDev(20); 
    objRef = objDev;

    objDev.Display(); 
    return 0; 
}

#include<iostream.h> 
class CuriousTab
{
    int x, y; 
    public:
    void SetValue(int &xx, int &yy)
    {
        x =  xx++;
        y =  yy; 
        cout<< xx << " " << yy;
    }
};
int main()
{
    int x = 10;
    int &y = x;
    CuriousTab objCuriousTab;
    objCuriousTab.SetValue(x , y);
    return 0; 
}

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

#include<iostream.h> 
enum xyz
{
    a, b, c
};
int main() 
{
    int x = a, y = b, z = c;
    int &p = x, &q = y, &r = z;
    p = ++x;
    q = ++y;
    r = ++c;
    cout<< p << q << r;
    return 0;
}