// Helene Martin, Garfield High School
// Demonstrates fencepost loops

public class FencepostExamples {
	public static void main(String[] args) {
		System.out.println(isPlural("sneakers"));
		System.out.println(isPlural("sneaker"));
		System.out.println(countSlowly(10));
		printNumbers(10);
		
		System.out.println();
		System.out.println(isPrime(21));
		System.out.println(isPrime(17));
		printPrimes(100);
	}
	//s.endsWith("s");
	//s.charAt(s.length() - 1) == 's'
	public static boolean isPlural(String s) {
		return s.charAt(s.length() - 1) == 's';
	}
	
	public static String countSlowly(int a) {
		String result = "";
		for(int i = 1; i <= a; i++) {
			result = result + i + "onethousand";
		}
		return result;
	}
	
	public static void printNumbers(int max) {
		System.out.print("1");
		for(int i = 2; i <= max; i++) {
			System.out.print(", " + i);
		}
	}
	
	public static void printNumbers2(int max) {
		for(int i = 1; i < max; i++) {
			System.out.print(i + ", ");
		}
		System.out.print(max);
	}
	
	// classic cummulative sum!!
	public static int countFactors(int num) {
		int factors = 0;
		for(int i = 2; i < num; i++) {
			if(num % i == 0) {
				factors++;
			}
		}
		return factors;
	}
	
	public static boolean isPrime(int num) {
		return countFactors(num) == 0;
	}
	
	public static void printPrimes(int max) {
		System.out.print("2");
		for(int i = 3; i <= max; i++) {
			if(isPrime(i)) {
				System.out.print(", " + i);
			}
		}
	}
}