g = strcmp(s1, s2); returns 0 when the strings are equal, a negative integer when s1 is less than s2, or a positive integer if s1 is greater than s2, that strcmp() not only returns -1, 0 and +1, but also other negative or positive values(returns difference between the first non-matching pair of characters between s1 and s2). A possible implementation for strcmp() in "The Standard C Library". int strcmp (const char * s1, const char * s2) { for(; *s1 == *s2; ++s1, ++s2) { if(*s1 == 0) return 0; } return *(unsigned char *)s1 < *(unsigned char *)s2 ? -1 : 1; }