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Collection exercise Scrabble

Simone Sarigu
Greenhorn

Joined: May 09, 2012
Posts: 7
Hello this is my first message. I'm learning Java and studying the collection framework. I've found an exercise that is driving me crazy. I'd like to have some advices to solve it.

this is the text:
Write a static method boolean componibile(List <character> l,String s) that, given a list of alphabetic characters (which includes also the wildcard '*') and a string, returns true if the
string can be composed using the characters in the list, and false otherwise. Write the solution in order to compile and run the following test schedule without having to edit it:

Thank you
Jeff Verdegan
Bartender

Joined: Jan 03, 2004
Posts: 6109
    
    6

Hi, and welcome to the Ranch!

You'll find your experience here a lot more productive and rewarding if you take your best shot at solving it yourself, show us what you've done so far, and ask a specific question about the specific bits that are giving you trouble.

And remember: Break the problem up into the smallest pieces you can, and work on solving one piece first before moving on to the next one.

Good luck!
Winston Gutkowski
Bartender

Joined: Mar 17, 2011
Posts: 7492
    
  18

Simone Sarigu wrote:this is the text:

Hi Simone, and welcome to JavaRanch.

I've broken up those very long lines of yours because they screw up the windowing here (it's also bad programming practise).

Please re-read the UseCodeTags (←click) page thoroughly.

Thanks.

Winston
Simone Sarigu
Greenhorn

Joined: May 09, 2012
Posts: 7
Ok I'm posting the class i've write. It doesn't work and throw a NoSuchElementException.
Hope this won't screw up the page again.



Thank you
Jeff Verdegan
Bartender

Joined: Jan 03, 2004
Posts: 6109
    
    6

It will be easier to help you if you copy/paste the exact, complete error message, including at least the first several lines of the stack trace, and indicate clearly which line caused the problem.
fred rosenberger
lowercase baba
Bartender

Joined: Oct 02, 2003
Posts: 11152
    
  16

We are always happy to help...but the details are always CRITICALLY important. "It doesn't work" doesn't really tell us the problem.

Does it compile? Does it run? Does it crash partway through?

I can guess that the latter is the case...but when it throws that exception, it gives you information on where EXACTLY that is happening. Please post the entire error message, not just a paraphrase of it.

I even went as far as trying to compile all your code. The ProvaScarabeo class gives me 6 errors. The Scarabeo compiles, but I can't run it since it doesn't have a main. So I can't help you any further.


There are only two hard things in computer science: cache invalidation, naming things, and off-by-one errors
Simone Sarigu
Greenhorn

Joined: May 09, 2012
Posts: 7
Thank you guys for your patience. In the ProvaScarabeo class was missing an import. I can't edit the first post: import java.util.*;


Exception in thread "main" java.util.NoSuchElementException
at java.util.ArrayList$Itr.next(ArrayList.java:794)
at esercizioundici.Scarabeo.arrChar(Scarabeo.java:38)
at esercizioundici.Scarabeo.componibile(Scarabeo.java:07)
at esercizioundici.ProvaScarabeo.main(ProvaScarabeo.java:24)
Java Result: 1

Campbell Ritchie
Sheriff

Joined: Oct 13, 2005
Posts: 37907
    
  22
That Exception suggests you are trying to get something out of the List which was never put into the List in the first place. Please make sure that all 26 letters have been entered into the List.
Jeff Verdegan
Bartender

Joined: Jan 03, 2004
Posts: 6109
    
    6

Exactly. You're calling next() when there is no next() element.
Simone Sarigu
Greenhorn

Joined: May 09, 2012
Posts: 7
Thanks to all. I tried to remove those loops inside the methods and use a counter as parameter and now works.
I can't figure out why the other way didn't work. Hints are appreciated ;)



 
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