Pointer to pointer in C | C Double pointer | My CS Tutorial

Pointer to pointer in C | Double pointer in C | Declaration of double pointer | Example of double pointer | C - pointer to pointer | Double pointer in C programing | My CS Tutorial

Double pointer(pointer to pointer) in C | My CS Tutorial

We know that a pointer holds the address of another variable of same type. When a pointer holds the address of another pointer then such type of pointer is known as pointer-to-pointer or double pointer.
In this post, we will learn what is a pointer to pointer(double pointer), how to declare them and how to use them in C programming. To understand this concept, you should know the basics of pointers.

Pointer to Pointer (Double pointer) in C

A pointer to a pointer is a form of multiple indirection, or a chain of pointers.
Normally, a pointer contains the address of a variable. When we define a pointer
to a pointer, the first pointer contains the address of the second pointer, which
points to the location that contains the actual value as shown below.

Structure of double pointer in c | My CS Tutorial

Declaration of double pointer

A variable that is a pointer to a pointer must be declared as such. This is done
by placing an additional asterisk in front of its name. For example, the following declaration declares a pointer to a pointer of type int:-

int **ptr;

When a target value is indirectly pointed to by a pointer to a pointer, accessing that value requires that the asterisk operator be applied twice, as is shown below in the example:

#include<stdio.h>
#include<conio.h>
int main()
{
int num=10;    
int *p;
int **p2;      
clrscr();

p=&num ;    
p2=&p ;  

printf("Num variable address is = %x \n",&num);    

printf("p variable address is =%x \n",p);    

printf("*p variable value is = %d \n",*p);    

printf("p2 variable address is = %x \n",p2);    

printf("**p2 variable value is =%d \n",*p);    

return 0;
}


Output of this program is given below:-

Num variable address is = bee79840
p variable address is =bee79840
*p variable value is = 10
p2 variable address is = bee7983c
**p2 variable value is =10


Pointer to pointer in C | Double pointer in C | Declaration of double pointer | Example of double pointer | C - pointer to pointer | Double pointer in C programing | My CS Tutorial

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Created by-- HARSH CHAUHAN