salieri:~/tmp% cat test.c
#include <stdio.h>

int
main ()
{
        if (0)
                printf ("0 works\n");

        if (1)
                printf ("1 works\n");

        if (-1)
                printf ("-1 works\n");

        if (9292)
                printf ("9292 works\n");

        return 0;
}
salieri:~/tmp% gcc -Wall test.c -o test
salieri:~/tmp% ./test
1 works
-1 works
9292 works