//pointer
#include<stdio.h>
void main()
{
int a, *b, **c, ***d;
a=2000;
b=&a;
c=&b;
d=&c;
printf("%d\t%d\t%d\t%d",a,b,c,d);
}
Here ‘a‘ is simple integer variable.While b, c and d is Pointer integer variables of different level. That is,
b is a pointer to an integer
c is a pointer to a pointer to a pointer to an integer.
d is a pointer to a pointer to a pointer to a pointer to an integer.
Which is called extended concept of Pointer.