#include <stdio.h>
#include <string.h>

int memmcmp(void *p1, void *p2, size_t len);

int main() {
   char *str1 = "suckysucky";
   char *str2 = "uuckysucky";
   char *p1  = str1;
   char *p2  = str2;
   int len   = strlen(str1);

   int res = memmcmp(p1,p2,len);

   printf("%d",res);

   return 0;
}

int memmcmp(void *p1, void *p2, size_t len) {
   char u1, u2;
   for(; len--; p1++, p2++) {
      u1 = *(char *) p1;
      u2 = *(char *) p2;
      if ( u1 != u2) {
         return (u1-u2);
      }
   }
}