// Zorah Fung, CSE 142
// Examples of methods that return booleans
import java.util.*;

public class BooleanMethods {
   public static void main(String[] args) {
      Scanner console = new Scanner(System.in);
      System.out.print("What is your age? ");
      int age = console.nextInt();
      if (isPrime(age)) {
         System.out.println("Welcome to the prime party!");
      }

      System.out.println(bothOdd(5, 7)); // true
      System.out.println(bothOdd(6, 4)); // false
      System.out.println(bothOdd(5, 4)); // false
      System.out.println(bothOdd(0, 7)); // false
      System.out.println(bothOdd(1, 5)); // true
      System.out.println(bothOdd(-5, -7)); // true 
     
      System.out.println("banana: " + hasVowel("banana"));
      System.out.println("crwth: " + hasVowel("crwth")); // valid word. great for scrabble   
   }
   
   // returns whether a value is a prime or not
   public static boolean isPrime(int value) {
      return factors(value) == 2;
      // Bad boolean zen!
      //       int factors = factors(value);
      //       if (factors == 2) {
      //          return true;
      //       } else {
      //          return false;
      //       }
   }
   
   // counts and returns the factors of a given number
   public static int factors(int value) {
      int factors = 0;
      for (int i = 1; i <= value; i++) {
         if (value % i == 0) {
            factors++;
         }
      }
      return factors;
   }
  
   // bothOdd returns true if both parameters are odd, false otherwise
   public static boolean bothOdd(int num1, int num2) {
      boolean num1Odd = num1 % 2 != 0;
      boolean num2Odd = num2 % 2 != 0;
      
      return num1Odd && num2Odd;
   }
 
   // Returns true if the given word contains a vowel, false otherwise
   public static boolean hasVowel(String word) {
      word = word.toLowerCase();
      for (int i = 0; i < word.length(); i++) {
         char c = word.charAt(i);
         if (isVowel(c)) {
            return true;
         }
      }
      return false; // must look at all letters before returning false
   }
   
   // Returns true if the given lowercase letter is a vowel, false otherwise
   // Note: the slides have a different version of isVowel that takes a String
   // as a parameter, which requires the use of the .equals string method
   public static boolean isVowel(char c) {
      boolean vowel = c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u';
      return vowel;
   }
   
   // Returns true if the given lowercase letter is not a vowel (consonant), false otherwise
   public static boolean isNonVowel(char c) {
      // Equivalent to !isVowel(c)
      // In order to negate the expression from isVowel, we both negate the tests
      // in each expression, as well as flip the logical operator from || to && using
      // DeMorgan's Law
      return c != 'a' &&  c != 'e' && c != 'i' && c != 'o' && c != 'u';
   }
}