rem: if (isupper((int) *s)) *s = tolower((int) *s);
add: if (isupper(* (unsigned char *) s)) *s = tolower(* (unsigned char *) s);
context: void strlower(char *s){	while (*s) {		if (isupper((int) *s))			*s = tolower((int) *s);		s++;	}}