Write a C Program to show an example of pointer to pointer

Pointer to Pointer :

• 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

• 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.

• The declaration of a pointer-to-pointer looks like :

• int **ipp;

• where the two asterisks indicate that two levels of pointers are involved.

Below is the source code for C Program to show an example of pointer to pointer which is successfully compiled and run on Windows System to produce desired output as shown below :

SOURCE CODE : :

/* Program to understand pointer to pointer*/

#include<stdio.h>

int main( )
{
        int a = 5;
        int *pa;
        int **ppa;
        pa = &a;
        ppa = &pa;
        printf("Address of a = %p\n", &a);
        printf("Value of pa = Address of a = %p\n", pa);
        printf("Value of *pa = Value of a = %d\n", *pa);
        printf("Address of pa = %p\n", &pa);
        printf("Value of ppa = Address of pa = %p\n", ppa);
        printf("Value of *ppa = Value of  pa = %p\n", *ppa);
        printf("Value of **ppa = Value of a = %d\n", **ppa);
        printf("Address of ppa = %p\n", &ppa);

    return 0;

}

OUTPUT : :

Address of a = 000000000062FE4C
Value of pa = Address of a = 000000000062FE4C
Value of *pa = Value of a = 5
Address of pa = 000000000062FE40
Value of ppa = Address of pa = 000000000062FE40
Value of *ppa = Value of  pa = 000000000062FE4C
Value of **ppa = Value of a = 5
Address of ppa = 000000000062FE38