Pointer to Pointer (Multiple Indirection)

Pointer which holds address of another pointer is called as pointer to pointer. It is also called as double pointer. 

Syntax: int **ptr_to_ptr; 

Example: 

int i=10; 

int *ptr; //pointer to an integer 

int **ptr_to_ptr: //pointer to a pointer 

ptr=&i; 

ptr_to_ptr = &ptr; 

C Program to illustrate pointer to pointer. 

#include<stdio.h>  

void main() 

{ 

int i=10,*p1,**p2; 

p1= &i; 

p2=&p1; 

printf(“\n the value of i is %d %d %d ”,i,*p1,**p2); 

printf(“\n the address of i is %u %u %u”,&i,p1,*p2); 

} 

In above program p1 is pointer and p2 is a pointer to pointer. 

Pointer to pointer is often used in handling of strings, multidimensional arrays. 

Also Read

1. Static and Dynamic Memory Allocation
2. Memory Leak and Dangling Pointer
3. Memory Allocation for 2D Array
4. Dynamic Memory Allocation
5. Pointer Constant and Constant Pointer
6. Pointer Declarations and their Meanings
7. Functions and Pointers
8. Initializing Pointer to Pointer
9. Relationship between Arrays and Pointers
10. Pointer to Array
11. Pointer Arithmetic
12. Types of Pointers
13. Illustrate Basic Pointer Use
14. Using Pointer
15. Intializing Pointer
16. Declaring Pointer
17. Application of Pointers
18. Value Model VS Reference Model
19. What is Pointer