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

#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; 
}

1. The information being returned is a large enough object that returning a reference is more efficient than returning a copy.
2. The type of the function must be a R-value.

#include<iostream.h> 
class PowerFinder
{
    public:
    void Power(int x = 1, int y = 1)
    {
        int P = 1, i = 1;
        while(++i <= y)
        {
            P *= x;
        }
        cout<< P << endl; 
    } 
};
int main()
{
    PowerFinder FP; 
    FP.Power(2, 6); 
    return 0;
}

#include<iostream.h> 
class BaseCounter
{
    protected:
    long int count;

    public:
    void CountIt(int x, int y = 10, int z = 20)
    {
        count = 0;
        cout<< x << " " << y << " " << z << endl;
    } 
    BaseCounter()
    {
        count = 0;
    }
    BaseCounter(int x)
    {
        count = x ;
    } 
}; 
class DerivedCounter: public BaseCounter
{
    public:
    DerivedCounter()
    { }
    DerivedCounter(int x): BaseCounter(x) 
    { }
};
int main()
{
    DerivedCounter objDC(30); 
    objDC.CountIt(40, 50); 
    return 0; 
}

#include<iostream.h> 
class CuriousTab
{
    static int x; 
    public:
    static void SetData(int xx)
    {
        this->x = xx; 
    }
    static void Display() 
    {
        cout<< x ;
    }
};
int CuriousTab::x = 0; 
int main()
{
    CuriousTab::SetData(22);
    CuriousTab::Display();
    return 0; 
}

#include<iostream.h> 
struct MyStructure
{
    class MyClass
    {
        public:
        void Display(int x, float y = 97.50, char ch = 'a')
        {
            cout<< x << " " << y << " " << ch;
        }
    }Cls; 
}Struc;
 
int main()
{
    Struc.Cls.Display(12, 'b');
    return 0; 
}

#include<iostream.h> 
class CuriousTab
{
    int x, y, z; 
    public:
    void Apply(int xx = 12, int yy = 21, int zz = 9)
    {
        x = xx;
        y = yy += 10;
        z = x -= 2;
    }
    void Display(void)
    {
        cout<< x << " " << y << endl; 
    } 
    void SetValue(int xx, int yy)
    {
        Apply(xx, 0, yy);
    }
};
int main()
{
    CuriousTab *pCuriousTab= new CuriousTab;
   (*pCuriousTab).SetValue(12, 20);
    pCuriousTab->Display();
    delete pCuriousTab;
    return 0; 
}