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

#include<iostream.h> 
class CuriousTab
{
    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()
{
    CuriousTab objCuriousTab;
    int x  = 2;
    int &y = x;
    y = 5;
    objCuriousTab.SetValue(x, ++y, x + y);
    objCuriousTab.Display();
    return 0; 
}

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

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

#include<iostream.h> 
int main()
{
    int arr[] = {1, 2 ,3, 4, 5}; 
    int &zarr = arr;
    for(int i = 0; i <= 4; i++)
    {
        arr[i] += arr[i];
    }
    for(i = 0; i <= 4; i++)
        cout<< zarr[i]; 
    return 0; 
}

#include<iostream.h> 
class CuriousTab
{
    int x, y; 
    public:
    void SetValue(int &a, int &b)
    {
        a = 100;
        x = a;
        y = b;
        Display();
    }
    void Display()
    {
        cout<< x << " " << y; 
    }
};
int main()
{
    int x = 10;
    CuriousTab objCuriousTab;
    objCuriousTab.SetValue(x, x);
    return 0;
}

#include<iostream> 
enum curioustab
{
    a=1, b, c
};
int main()
{
    int x = c;
    int &y = x;
    int &z = x;
    y = b;
    std::cout<< z--;
    return 0; 
}

#include<iostream.h> 
int main()
{
    int x = 10, y = 20;
    int *ptr = &x;
    int &ref = y;

    *ptr++;
     ref++;    

    cout<< x << " " << y;
    return 0; 
}

#include<iostream.h> 
class CuriousTabTest
{
    public:
    CuriousTabTest(int &x, int &y)
    {
        x++;
        y++;
    } 
};
int main()
{
    int a = 10, b = 20;
    CuriousTabTest objBT(a, b); 
    cout<< a << " " << b; 
    return 0; 
}

#include<iostream.h> 
int main()
{
    int x = 0;
    int &y = x; y = 5; 
    while(x <= 5)
    {
        cout<< y++ << " ";
        x++;
    }
    cout<< x; 
    return 0; 
}

#include<iostream.h> 
int main()
{
    int x = 10;
    int &y = x;
    x = 25;
    y = 50;
    cout<< x << " " << --y;
    return 0; 
}

#include<iostream.h> 
int main()
{
    int m = 2, n = 6;
    int &x = m++;
    int &y = n++;
    m = x++; 
    x = m++;
    n = y++;
    y = n++;
    cout<< m << " " << n; 
    return 0; 
}