C++ program to perform addition and multiplication using inheritance

#include<iostream.h>
#include<conio.h>
class a{
public:
int no1, no2;
void put();
};
void a::put(){
cout<<"Enter two numbers:-"<<endl;
cin>>no1>>no2;
}
class b:public virtual a{
public:
int sum;
void add();
};
void b::add(){
sum=no1+no2;
}
class c:public virtual a{
public:
int pro;
void multiply();
};
void c::multiply(){
pro=no1*no2;
}
class d:public b, public c{
public:
display();
};
void d::display(){
cout<<"Sum: "<<sum<<"\nProduct: "<<pro<<endl;
}
void main(){
d obj();
clrscr();
d.put();
d.add();
d.multiply();
d.display();
getch();
}