#include <string.h>
#include <ctype.h>

int strcasecmp(const char *s1, const char *s2)
{
	while (*s1 != '\0' && *s2 != '\0' && tolower(*s1) == tolower(*s2)) {
		s1 += 1;
		s2 += 1;
	}
	return (*s1 - *s2);
}