multilevel inheritance with private and protected

#include <iostream.h>

#include <conio.h>

class mm

{

private:

int rollno;

public:

void get_num(int a)

{ rollno = a; }

void put_num()

{ cout << "Roll Number Is:"<< rollno << "\n"; }

}; class marks : public mm

{

protected:

int sub1;

int sub2;

public:

void get_marks(int x,int y)

{

sub1 = x;

sub2 = y;

}

void put_marks(void)

{

cout << "\nSubject 1:" << sub1;

cout << "\nSubject 2:" << sub2;

}

}; class res : public marks

{

protected:

float tot;

public:

void disp(void)

{

tot = sub1+sub2;

put_num();

put_marks();

cout << "\nTotal:"<< tot;

}

}; int main()

{

res std1;

std1.get_num(5);

std1.get_marks(10,20);

std1.disp();

getch();

}