// This is a particularly elegant solution.  Your solution doesn't have to be this
// compact.

import java.util.*;

/**
 * Assignment 1: Self Divisor
 *
 * 
 * @author	    Student From COMP401
 * <p>
 * <b>TA:</b> 	    Catalin Constantin.
 * <p>
 * <b>Recitation section:</b> Comp401.602
 * <p>
 * <b>Date:</b>        February 7, 2008
 * <br><br>
 * <b>Pledged:</b>     I have neither given nor received unauthorized aid on
 *              this program.
 *
 * <br> <br>    <sign here>____________________________
 * <p>
 * <b>Description: </b>
 *             This program generates an array of self divisors which are then
 *             displayed on the screen. The program asks for two input parameters:
 *             the base number to start from, and a count of how many self divisors 
 *             should the array have. A self divisor is a number divisible by all
 *             of its digits.
 *
 *  <br><br>
 * <b>Input: </b> The base and the count.
 * <br><br>
 * <b>Output:</b> Greeting and list of self divisors. 
 * <br><br>
 * <b> Errors checked for: </b> none
 * <br><br>
 * <b> Restrictions: </b> Both the starting integer (base) and the number of self divisors
 * 						(count) need to be greater than 0.         
 *
 */
public class SelfDivisors 

{
	/**
	 * The main method. It loops asking for input until a 0 or negative
	 * base is entered.
	 * @param args standard
	 */
	public static void main(String[] args)
	{
		Scanner kb = new Scanner(System.in);
		
		/* greeting and info */
		System.out.println("This program will generate a list of self divisors.");
		
		/* getting input parameters from the user */
		System.out.print("\n\nHow many self divisors: ");
		int count = kb.nextInt();
		System.out.print("Enter starting number (0 finish): ");
		int base = kb.nextInt();
		
		/* loop until 0 or negative */
		while(base>0)
		{
			/* obtain the list of self divisors */
			int[] sdArray = selfDivArray(base, count);
			
			/* print out the self divisors */
			System.out.println("\n" + count + " self divisors from "+ base);
			for(int i=0; i<sdArray.length; i++)
				System.out.println("("+(i+1)+"): " + sdArray[i]);
			
			/* getting input parameters from the user again */
			System.out.print("\n\nHow many self divisors: ");
			count = kb.nextInt();
			System.out.print("Enter starting number (0 finish): ");
			base = kb.nextInt();
		}
		
		System.out.print("End of job.");
	} //main
	
	
	/**
	 * Generates an array of self divisors.
	 * @param base the start number to search from
	 * @param count the number of self divisors in the array
	 * @return the array of self divisors
	 */
	public static int[] selfDivArray(int base, int count)
	{
		int[] sdArray = new int[count];
		
		/* loop and add the self divisors to the array */
		for(int i=0; i<count; i++)
		{
			while(!isSelfDiv(base++));
			sdArray[i] = base-1;
		}
		
		return sdArray;
	} //selfDivArray
	
	/**
	 * Tests self divisor property for a single integer.
	 * @param n the integer to be checked
	 * @return true if a self divisor, false otherwise
	 */
	public static boolean isSelfDiv(int n)
	{
		
		boolean valid = (n>0); /* positive values only */
		
		/* k - working version of the input number, that gets shorter
		 * after each iteration. r - last digit, after modulus division 
		 * by 10. Self divisor test implies that r should not be 0, and
		 * r should divide n evenly 
		 */
		for(int k=n, r=k%10; valid && k>0; k/=10, r=k%10)
			valid = !((r==0) || (n%r!=0));
		
		return valid;
	} // isSelfDiv
}