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Thread: Having trouble with my code, please help!

  1. #1
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    Default Having trouble with my code, please help!

    Part of my program requires writing a function that determines the number of subsets of k items that can be chosen from a set of n distinct objects ("n choose k" or n!/((n-k)! n!)). The only errors I am getting are from the first line of the function:

    // n choose k: distinct subsets of k items chosen from n items
         public static int choose (int n, int k) {
          if (k <= 0)
            return 1;
          else
            return choose(n--, k--) * (n/k);
        }

    Any help that I can get to find out what is wrong with this would be extremely helpful. Thanks!


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    Default Re: Having trouble with my code, please help!

    Welcome to the forum! Please read this topic to learn how to post code in code or highlight tags and other useful info for new members.

    What do you mean, "find out what is wrong with it?" What does the error say? Post the entire error message if you don't understand it and perhaps we can help you with understanding it. Otherwise, you haven't given us enough information to help you. Post something we can work with.

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    Default Re: Having trouble with my code, please help!

    By the way, I would advice you not to use the "--" operator the way you do. It might easily confuse you since its not too obvious to a beginner what it actually does.
    Your line:
    return choose(n--, k--) * (n/k);
    is equal to:
    return choose(n, k) * ((n - 1) / (k - 1));
    and I doubt this is what you want because it will end in infinite recursion.

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