Which of the following statements is correct when a class is inherited privately?

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

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