Homework assignment 3 - Juli. Class of 2019

/*
    [PROBLEM 3 OVERVIEW]
    Operating System: Linux
    Difficulty: Easy

    [PROBLEM 3 DESCRIPTION]
    The code below contains a unique take on the infamous "fizzbuzz" problem.
    You are tasked with modifying the 'system' variable in order to have getFavoriteFood() return a positive number.
    The current implementation below will output a negative number to stdout.
    An approach that involves "guess-and-check" is valid, but try to understand why certain inputs pass and why others fail.
    Feel free to reach out to your peers, tutors, or other online resources if you need additional help.

    [PROBLEM 3 FOOD MENU]
    #1: Spaghetti
    #2: Chicken Fettuccine
    #3: Cheeseburger
    #4: Pepperoni Pizza
    #5: Caeser Salad
*/

#include <stdio.h>
#include <stdlib.h>

#define SECRET_NUM 29

typedef int (*StringToInt)(const char *text);

int getFavoriteFood(int *secret, StringToInt atoi)
{
  char *favorite_food = (char *)calloc(SECRET_NUM, sizeof(char));

  for (int i = 0; i < SECRET_NUM; i++)
  {
    int counter = secret[i / 4] >> (i % 4 * 8) & 255;

    if (i % 3 == 0)
      favorite_food[i] = counter ^ 3;
    else if (i % 5 == 0)
      favorite_food[i] = counter ^ 5;
    else
      favorite_food[i] = counter ^ 15;
  }

  return atoi(favorite_food);
}

int main()
{
  int _secret[] = {1818717286, 1617895983, 1803363171, 728642596, 1847817254, 690971257, 1647605795, 15};
  int _system = '3';

  printf("Problem 3: Favorite Food is %d", getFavoriteFood(_secret, (StringToInt)system));

  return 0;
}