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Thread: Help with a for loop and formating

  1. #1
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    Default Help with a for loop and formating

    Hey! Im going to make a program that prints out this to the console: 123123.jpg

    Anyone got any thoughts on how to do it? I think it has something to do with a for loop and some formatting of the output.. please help with some thoughts


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    Default Re: Help with a for loop and formating

    Your thoughts are good enough to get started. Come back with some code when you need help with it.

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    Default Re: Help with a for loop and formating

    Ive come up with something, its almost done:
    private static void printNumbersB(int n) {
     
     
    		int teller = 1;
     
    		for (int lineNumber = 1; lineNumber <= n; lineNumber++) {
    			        for (int currentField = 1; currentField <= lineNumber; currentField++) {
    			          System.out.printf ("%" + lineNumber + "d", teller);
     
    			          teller += 1;
    			        }
    			        // Blank line
    			       System.out.println();
     
     
    		}
     
    	}

    All i need for it now is to stop printing numbers when it has reached the N parameter, any thoughts?

    --- Update ---

    Nevermind! Found out if i added a if statement to the end where it breaks out of the loop if the teller is higher than N, worked!

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    Default Re: Help with a for loop and formating

    Got some problems now, if i put 45 as a parameter, it prints out correctly like this: 123123.jpg, but if i put it to for example 95, it turns out like this: Untitled123.jpg Somehow it doesnt stop on 95 if i put the parameter higher than 45?O.o

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    Default Re: Help with a for loop and formating

    This is excellent. You've done good work with no help, just thinking it through and coding.

    It's hard to see from the little pictures what your complaint(s) is/(are). Can you describe better what's going wrong?

    Also, post the full updated code (in code tags, please) so that we can see the results for ourselves. Let us know what we need to do to run the code to duplicate the problem condition you've found.

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    Default Re: Help with a for loop and formating

    My current issues:
    If i put the parameter to 56, it prints out numbers up to 55. But if i put the parameter to 57, it prints out numbers up to 66??
    Heres the current code:

    private static void printNumbersB(int n) {
     
     
    		int teller = 1;
     
    		for (int linjenummer = 1; linjenummer <= n; linjenummer++) {
    			        for (int currentField = 0; currentField < linjenummer; currentField++) {
    			          System.out.printf ("%" + linjenummer + "d", teller);
     
    			          teller += 1;
     
    			        }
    			        // Blank line
    			       System.out.println();
     
    			       if (teller >= n)	{
    			    	   break;
    			       }
     
    		}

    To run it you have to call it in the mainmethod with a parameter value (which you probably know)

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    Default Re: Help with a for loop and formating

    There are a couple things causing your confusion. First, I've changed the indenting of your code so that it may be easier to see what's going on. Like so:
    private static void printNumbersB(int n)
    {
    	int teller = 1;
     
    	for (int linjenummer = 1; linjenummer <= n; linjenummer++)
    	{
    		for (int currentField = 0; currentField < linjenummer; currentField++)
    		{
    			System.out.printf ("%" + linjenummer + "d", teller);
     
    			teller += 1;
    		}
    		// Blank line
    		System.out.println();
     
                    // changed to a return
    		if (teller >= n)
    		{
    			return;
    		}
     
    	}
    }
    There are two loops, one inside the other, known as "nested for loops" or some people say "bifurcated loops." Your test for exiting the looping uses the outside loop's control variable, but the test isn't made until after the inside loop completes. If you study the looping, you'll see that some numbers chosen for 'n' will fall on a boundary that will end the program when you'd like, but others will require the inside loop to finish - printing the extra numbers you're complaining about - before exiting the loop.

    In short, either move or change the test. I think you'll find moving the current test does not provide exactly what you want, because I think you want it to stop printing at those boundary points that print the entire line and no more. Changing the test to only print the last whole line that's less than the number 'n' is what I think you're after. You'll have to compute where those line boundaries < n fall and end there.

    I changed the 'break' to a 'return', because it unambiguously indicates what you want to happen at that point.

  8. The Following User Says Thank You to GregBrannon For This Useful Post:

    Oldemor (October 20th, 2013)

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    Default Re: Help with a for loop and formating

    Ah Thank you for your expertise. I moved the test, and it worked like i was hoping it to do. Its okay that it doesn't print the whole line, as of now! Have a great day.

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