#include <stdio.h> int main(){   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");    return 0;} /* vim: set expandtab ts=4 sw=3 sts=3 tw=80 :*/