#include <string.h>
int strcmp(const char* s1, const char* s2)
{
const unsigned char* u1 = (unsigned char*)s1;
const unsigned char* u2 = (unsigned char*)s2;
for (; *u1 && *u2; u1++, u2++)
if (*u1 != *u2)
break;
return *u1 - *u2;
}