import java.util.Scanner;
// Examples of how Iteration works in Java
// Ferworn Fall 02 updated Fall 05

public class Iteration
{
	public static void main(String[] args)
	{
		Scanner Keyboard = new Scanner(System.in);

		int num = 10, other = 10;

		// Demo 1: a simple while loop 
		System.out.println("***Demo 1");
		System.out.println("num is: " + num);
		while(num > 0)
			num--;
		System.out.println("num is: " + num);


		// Demo 2: a while loop with a block
		System.out.println("***Demo 2");
		while(num < 10)
		{
			num++;
			System.out.println(num);
		}

		// Demo 3: forcing correct input using while 
		// (0 or more times iteration)
		System.out.println("***Demo 3");
		num = 1;
		while(num != 0)
		{
			System.out.println("Please enter the number 0");
			num = Keyboard.nextInt();
		}

		//Demo 4: a simple do while loop
		//Used where you need to perform the body of the loop
		//at least once and possibly more times.
		System.out.println("***Demo 4");
		num = 5;
		do
		{
			System.out.println
			("This code will be executed at least once");
			num = 0;
		}while(num != 0);

		//Demo 5: forcing correct input using 
		//do while (An example of "Mall Rat code"
		System.out.println("***Demo 5");
		do
		{
			System.out.println("Please enter the number 0");
			num = Keyboard.nextInt();
		}while(num != 0);

		//Demo 5A: forcing correct input using do while 
		//(more than 1 choice)
		System.out.println("***Demo 5A");
		do
		{
			System.out.println
				("Please enter the number 0,1 or 2");
			num = Keyboard.nextInt();
		}while((num != 0) && (num != 1) && (num != 2));;

		//Demo 6: Nesting loops (count up to 39..weirdly)
		System.out.println("***Demo 6");
		String numstring = new String();
		num = 0;
		other = 0;
		while(num <= 3)
		{
			while(other <= 9)
			{
				numstring = "" + num + "" + other;
				System.out.println(numstring);
				other++;
			}
			other = 0;
			num++;
		}

		//Demo 7: simple for loop (use "for" when 
		//you know how many times through)
		System.out.println("***Demo 7");
		for(num=0;num<10;num++)
			System.out.println(num);

		//Demo 8: nested for loop replicating Demo 6.
		System.out.println("***Demo 8");
		for(num=0;num<=3;num++)
			for(other=0;other<10;other++)
			{
				numstring = "" + num + "" + other;
				System.out.println(numstring);
			}

		//Demo 9: more about break.
		System.out.println("***Demo 9");
		while(true)
			break;

		//Demo 10: exercise. given "rows" and "columns" 
		//print a "block" of 
		//asterisks (*).
		//For example if rows=3 and columns=4 then
		//****
		//****
		//****
		System.out.println("***Demo 10");

		//Easy way!
		System.out.println("****");
                System.out.println("****");                
		System.out.println("****");			

		//More general way
		for(int i=0;i<3;i++)
		{
			for(int j=0;j<4;j++)
				System.out.print("*");
			System.out.println();
		}
	}
}