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


// a seemingly innocent password-checker
// (assuming ans is hidden and ans has len 8)

bool check(char *guess, char *ans) {

  int i=0;

  for(; i < 8; i++) {
    sleep(1); // I'm just emphasizing the problem to make it easier to measure
    if(guess[i] != ans[i]) {
      return false;
    }
  }
  return true;
}

// if can only check answers, exhaustive search
// required.
// but if can see timing, linear time


// better:
bool check2(char *guess, char *ans) {

  int i=0;

  bool result = true;

  for(; i < 8; i++) {
    sleep(1); // Using same delay as above
    if(guess[i] != ans[i]) {
      result = false;
    }
  }
  return result;
}


int main(int argc, char** argv) {

  char ans[] = "12345678";

  if ( argc > 1 && (strlen(argv[1])==8)) {
    printf("Password check: %d\n", check(argv[1],ans));
  }
  return 0;
}