#include <stdint.h>
#include <stdio.h>
#define ZERO 0
int main() {
int* pointer;
printf("Null pointer checks\n");
pointer = NULL;
printf(" pointer = NULL\n");
// ALWAYS VALID
printf("\tpointer == NULL\t\t");
(pointer == NULL) ? printf("true\n") : printf("false\n");
printf("\tpointer == 0\t\t");
(pointer == 0) ? printf("true\n") : printf("false\n");
printf("\t(!pointer)\t\t");
(!pointer) ? printf("true\n") : printf("false\n");
// POSSIBLY VALID
printf("\tpointer == '\\0'\t\t");
(pointer == '\0') ? printf("true\n") : printf("false\n");
printf("\tpointer == (void*)0\t");
(pointer == (void*)0) ? printf("true\n") : printf("false\n");
// INVALID
int x = 0;
printf("\tx = 0; pointer == x\t");
(pointer == x) ? printf("true (warning)\n") : printf("false\n");
// invalid check because `zero` is not a constant literal 0
// Should generate at least a warning according to c standard.
return 0;
}
