Multi-level inheritance

#include<iostream.h>
#include<conio.h>
class A
{
public:
int a,b;
void getdata()
{
cout<<"Enter two numbers:";
cin>>a;
cin>>b;
}
};
class B:public A
{
public:
int c;
void add()
{
c=a+b;
}
};
class C:public B
{
public:
void disp()
{
getdata();
add();
cout<<"sum of two numbers:";
cout<<c;
}
};
void main()
{
C c;
clrscr();
c.disp();
getch();
}