// CSE 142 Lecture 12
// Random, boolean
// Demonstrates boolean returns, application of DeMorgan's law.
public class Booleans {
	public static void main(String[] args) {
		System.out.println(isVowel("a"));
		System.out.println(isVowel("O"));
		System.out.println(isVowel("q"));
		System.out.println(isVowel("R"));
		System.out.println();
		
		System.out.println(isNonVowel("a"));
		System.out.println(isNonVowel("O"));
		System.out.println(isNonVowel("q"));
		System.out.println(isNonVowel("R"));
		System.out.println();
		
		System.out.println(hasVowel("FOO"));
		System.out.println(hasVowel("why"));
	}
	
	public static boolean isVowel(String s) {
		s = s.toLowerCase();
		return s.equals("a") || s.equals("e") || s.equals("i") || s.equals("o") || s.equals("u");
	}
	
	public static boolean isNonVowel(String s) {
		// Our same condition with DeMorgan's law applied
		// s = s.toLowerCase();
		// return !s.equals("a") && !s.equals("e") && !s.equals("i") && !s.equals("o") && !s.equals("u");
		return !isVowel(s);
	}
	
	public static boolean hasVowel(String s) {
		for (int i = 0; i < s.length(); i++) {
			String curLetter = s.substring(i, i + 1);
			if (isVowel(curLetter)) {
				return true;
			}
		}
		return false;
	}
}