Help needen with Pool Puzzle excercise on page 91 Head First book...pleaseee

[Krisztina Tarko]

Hi..

I am struggling since more than 1 hour on finding where the mistakes lies in my code from the Puzzle Exercise ..

Here is how I solved the exercise:

  
 public class Puzzle4 {


	public static void main(String[] args) {
		
		Puzzle4b[] obs = new Puzzle4b[6];
		
		int y = 1;
		int x = 0;
		int result = 0;
		
		while (x < 6) {
			obs[x] = new Puzzle4b();
			obs[x].ivar = y;
			y = y * 10;
			x = x + 1;
		}
		
		x = 6;
		
		while (x > 0) {
			x = x - 1;
			result = result + obs[x].doStuff(x);
		}
		System.out.println("result " + result);
	}

	class Puzzle4b {
		int ivar;
		public int doStuff (int factor) {
			if (ivar > 100) {
				return ivar * factor;
			} else { 
				return ivar * (5 - factor);
			}
		}
	}
}
  

And even though i really CAN'T see any difference from the given solution in the book..i get the following error:

Exception in thread "main" java.lang.Error: Unresolved compilation problem: 
	Type mismatch: cannot convert from Puzzle4 to Puzzle4.Puzzle4b

	at Puzzle4.main(Puzzle4.java:14)

Can someone see where i'm wrong..you know how they say: another pair of eyes always help:)
Many many thanks
Kris.

[pete stein]

I'd take Puzzle4b out of the Puzzle4 class. Make it a stand-alone class. Otherwise you'll need to do funny and ugly constructs like this one:

obs[x] = new Puzzle4().new Puzzle4b();

One other option is to make Puzzle4b a static inner class:

static class Puzzle4b
{
  //...

[Krisztina Tarko]

Yeah..that was it... i had the feeling that at this level it works to have them all in one..My mistake!!

Thanks a lot!

A good day!

[Rob Spoor]

Next time, check out the compiler errors (and to a lesser extent its warnings) before running your code.

[Krisztina Tarko]

Yes I know..it was a stupid mistake ..and sorry for takin your time with it..i just was stuck. But learned a good lesson!
again: Thanks a lot for your quick reply!

I promiss I won't be bothering again with such obvious things:)