Program for Multilevel Inheritance Using OOPs & C++ concept

#include<iostream.h>
#include<conio.h>
class A
{
int a;
public:
void fungeta()
{
a=10;
}
void funputa()
{
cout<<"A::"<<a;
}
};
class B:public A
{
int b;
public:
void fungetb()
{
fungeta();
b=20;
}
void funputb()
{
funputa();
cout<<"B::"<<b;
}
};
class C:public B
{
int c;
public:
void fungetc()
{
fungetb();
c=30;
}
void funputc()
{
funputb();
cout<<"C::"<<c;
}
};
class D:public C
{
int d;
public:
void fungetd()
{
fungetc();
d=40;
}
void funputd()
{
funputc();
cout<<"D::"<<d;
}
};
void main()
{
clrscr();
d obj;
obj.fungetd();
obj.funputd();
getche();
}