// Helene Martin, CSE 142
// These examples demonstrate ways to address fencepost problems, applications of 
// the cumulative sum pattern and methods that return.

public class LoopsDemo {
	public static void main(String[] args) {
		//printConsonants("all work and no play make jack a dull boy");
		//printLetters("all work and no play make jack a dull boy");
		
		System.out.println(countFactors(20));
		printPrimes(50);
	}
	
	// prints all primes up to and including the max
	// precondition: max is >= 2
	public static void printPrimes(int max) {
		System.out.print(2);	// extra 'post' in fencepost problem
		for (int i = 3; i <= max; i++) {
			if (countFactors(i) == 2) {
				System.out.print(", " + i);
			}
		}
	}
	
	// counts and returns the factors of a particular number
	public static int countFactors(int num) {
		int count = 0;
		for (int i = 1; i <= num; i++) {
			if (num % i == 0) {
				count++;
			}
		}
		return count;
	}
	
	// prints non-vowel letters from the phrase
	// e.g.: vowels -> vwls
	public static void printConsonants(String phrase) {
		for (int i = 0; i <= phrase.length() - 1; i++) {
			char c = phrase.charAt(i);
			if (c != 'a' && c != 'e' && c != 'i' && c != 'o' && c != 'u') {
				System.out.print(c);
			}
		}
	}
	
	// prints letters from the phrase separated by commas
	// e.g.: vowels -> v, o, w, e, l, s
	// this solution takes out the extra 'post' last 
	public static void printLetters(String phrase) {
		for (int i = 0; i < phrase.length() - 1; i++) {
			char c = phrase.charAt(i);
			System.out.print(c + ", ");
		}
		System.out.print(phrase.charAt(phrase.length() - 1)); // post
	}
	
	// prints letters from the phrase separated by commas
	// e.g.: vowels -> v, o, w, e, l, s
	// this solution takes out the extra 'post' first
	public static void printLetters2(String phrase) {
		System.out.print(phrase.charAt(0)); // post
		for (int i = 1; i < phrase.length(); i++) {
			char c = phrase.charAt(i);
			System.out.print(", " + c); // switch order in loop
		}
	}
}