picoc/tests/19_pointer_arithmetic.c

#include <stdio.h>

int a;
int *b;
int *c;

a = 42;
b = &a;
c = NULL;

printf("%d\n", *b);

if (b == NULL)
    printf("b is NULL\n");
else
    printf("b is not NULL\n");

if (c == NULL)
    printf("c is NULL\n");
else
    printf("c is not NULL\n");