/*
* return 0 iff s1 is the same string as s2
* return < 0 iff s1 is lexicographically less than s2
* return > 0 otherwise
*/
int
strcmp(char *s1, char *s2) {
int i;
for (i = 0; s1[i] == s2[i]; i++)
if (s1[i] == '\0')
return 0;
return s1[i] - s2[i];
}