What is a null pointer in C?

 

In C, a null pointer is a pointer that does not point to any memory location. It is a special constant value typically represented by the macro `NULL`. When a pointer is assigned the value `NULL`, it indicates that it does not point to a valid memory location.

Here's an example of using a null pointer:

int main() {

    int *ptr = NULL;  // Initializing a pointer with a null value

    

    if (ptr == NULL) {

        printf("The pointer is NULL\n");

    } else {

        printf("The pointer is not NULL\n");

    }

    

    return 0;

}

In this example, `ptr` is explicitly assigned the value `NULL`. Checking if a pointer is `NULL` is a common practice to ensure that the pointer is valid before dereferencing it to avoid potential runtime errors.