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Thread: Problem with arrays

  1. #1
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    Default Problem with arrays

    Good evening everyone , I am curently having problem since i want to make a basic program which basically reverse all the numbers of a certain array into the same array , by that i mean i want to overwrite my array into a new one but with it's number changed. I am still a basic programmer so sorry for not understanding my problem thank you.
    public class Reverse {
    	public static void main(String[] args) {
    		int [] numbers = {1,2,3,4,5,6,7,8,9};
    		reverseInPlace(numbers);
     
     
    	}
     
    	public static void reverseInPlace(int[] a) {
    		a = new int[10];
    		for (int i = 0; i <= a.length / 2; i++) {
    			int temp = a[i];
    			a[i] = a[a.length - 1 - i];
    			a[a.length-1-i]=temp;
    		}
     
    	}
    }


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    Default Re: Problem with arrays

    What problems are you having with the program?

    The Arrays class's toString() method is useful for formatting an array for printing:
    System.out.println("an ID "+ java.util.Arrays.toString(theArrayName));
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: Problem with arrays

    The problem is that i get no output , i know how to use arrays.ToString but the problem is i get no output.

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    Default Re: Problem with arrays

    What code do you expect to produce any output? I don't see any println() statements in the code.
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    Default Re: Problem with arrays

    Probably because when you pass the array into the reverseInPlace() method, you immediate reset it to a list of 10 zeros (that's what the first line in your method does). So when you run the loop, you are operating on all 0s, so of course you won't get the output you want.
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