// CSE 142, Winter 2008, Marty Stepp
// 
// This program demonstrates:
// - breaking apart a number into its digits
// - methods with while loops that compute and return values (digitSum)
// - methods with while loops that return boolean values (hasAnOddDigit, allDigitsOdd)

import java.util.*;   // for Random

public class Digits {
	public static void main(String[] args) {
		System.out.println("digit sum of 29107 = " + digitSum(29107));
		System.out.println("digit sum of 1112  = " + digitSum(1112));
		System.out.println("digit sum of 85    = " + digitSum(85));
		System.out.println("digit sum of 0     = " + digitSum(0));

		if (hasAnOddDigit(4822116)) {
			System.out.println("4822116 has an odd digit!");
		}
		if (hasAnOddDigit(2448)) {
			System.out.println("4822116 has an odd digit!");
		}

		if (allDigitsOdd(1353179)) {
			System.out.println("1353179 has all odd digits!");
		}
		if (allDigitsOdd(9175293)) {
			System.out.println("9175293 has all odd digits!");
		}
		if (allDigitsOdd(2468)) {
			System.out.println("2468 has all odd digits!");
		}
	}
	
	// Returns the sum of the digits of the given number.
	// For example, digitSum(29107) returns 2+9+1+0+7 or 19.
	public static int digitSum(int number) {   // 29107
		int sum = 0;
		while (number > 0) {
			int lastDigit = number % 10;         // 7     0    1
			sum = sum + lastDigit;
			number = number / 10;                // 2910  291  29
		}
		return sum;
	}

	// Returns true if the given number has any digit whose value is an odd number,
	// and false if every digit of the number is even.
	public static boolean hasAnOddDigit(int number) {
		while (number > 0) {
			int lastDigit = number % 10;
			if (lastDigit % 2 == 1) {
				// this is an odd digit; number must have an odd digit now
				return true;
			}
			number = number / 10;
		}
		
		// if I get here, there were no odd digits
		return false;
	}
	
	// Returns true if every digit of the given number is an odd number.
	public static boolean allDigitsOdd(int number) {
		while (number > 0) {
			int lastDigit = number % 10;
			if (lastDigit % 2 == 0) {
				// this is an even digit; all digits can't be odd now
				return false;
			}
			number = number / 10;
		}
		
		// if I get here, there were no even digits
		return true;
	}
}