text: #include "string.h"
  
  uint64_t strlen(char* str) {
    char* s;
    for (s = str; *s; ++s)
      ;
    return (s - str);
  }
  
  int strcmp(char* s1, char* s2) {
    for (; *s1 == *s2; s1++, s2++)
      if (*s1 == '\0')
        return 0;
    return ((*(unsigned char*)s1 < *(unsigned char*)s2) ? -1 : +1);
  }
  