octal.c

char *octalfive(unsigned int num) {
  char *repr = (char *) malloc(BINARY_REPR_LEN * num);
  unsigned int len;

  sprintf(repr, "%05o", num);
  len = strlen(repr);
  memmove(repr, repr + (len - 5), 5);
  return realloc(repr, 5);
}