Null Pointer

It is a pointer that does not point to any memory location.  It represents an invalid memory location.

When NULL value is assigned to a pointer, then it is considered as NULL Pointer.

Uses of NULL Pointer:

1. Used to initialise pointer
2. Useful to handling errors in dynamic memory allocation

The value of NULL is 0.  We can use either NULL or 0 to initialise pointer but 0 is not integer here.

Size of the NULL pointer depends upon the platform and is similar to the size of normal pointer.

It is a good practice to initialise a pointer as NULL.

It is also a good practice to perform NULL check before dereferencing any pointer to avoid surprises.

#include<stdio.h>

void main()

{

    int *ptr=NULL;

    printf(“%d”,ptr);

    printf(“n%d”,sizeof(NULL));

}