#include<stdio.h>  
int main(){  
int number=20;      
int *p;//pointer to int    
int **p2;//pointer to pointer        
p=&number;//stores the address of number variable      
p2=&p;    
printf("Address of number variable is %x \n",&number);      
printf("Address of p variable is %x \n",p);      
printf("Value of *p variable is %d \n",*p);      
printf("Address of p2 variable is %x \n",p2);      
printf("Value of **p2 variable is %d \n",*p);      
return 0;  
}