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Thread: Recursion Help

  1. #1
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    Default Recursion Help

    I'm having problems finishing my java homework - please help
    I need to write a method that draws an upside down pattern based on a given string (what the pattern is made of), and an int n (how many lines it has). So far I've managed to get it to work, but only the "right side up." What am I doing wrong?
    This is the code I have now:
    public static void printPattern(String str, int n) {
            if (n < 1) {
                return;
            }
    	System.out.println(str);
            printPattern(str + str, n - 1);
        }
    Example: for printPattern("*", 4) I currently get:

    *
    **
    ****
    ********

    and I'm supposed to get:

    ********
    ****
    **
    *

    Please help. Thanks in advance!
    Last edited by helloworld922; April 2nd, 2010 at 12:02 AM.


  2. #2
    Administrator copeg's Avatar
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    Default Re: Recursion Help

    Reversing recursive functions...think about order (aka order of calls)

  3. #3
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    Default Re: Recursion Help

    I'm not getting it. How would i reverse the order of calls for this piece of code?

  4. #4
    Super Moderator helloworld922's Avatar
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    Default Re: Recursion Help

    put what you get into a stack and just pop stuff off the stack.

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