How to shift array elements after removing one?

Question

I need to add a shift function only with loops (it means I can't use any ListArray method et simila, so this is not a copy of any other question with those methods.) to this method which removes a specific integer from a given array, and put the outcome into another array, and then returning it.

public static int[] removeInt(int v, int[] in) {

    int length = 0;
    length = in.length;
    int[] toReturn = new int[length];

    for (int b = 0; b < length; b++) {
        toReturn[b] = 0;
    }

    for (int i = 0; i < length; i++) {
        if (in[i] != v) {
            toReturn[i] = in[i];
        }
    }

    return toReturn;
}

If the input for the array is {1, 2, 3, 4, 5}, and the number to remove is {2}, the output will be {1 0 3 4 5}, but it needs to be {1 3 4 5}, and I can't find a way to shift numbers to the left.

'v' comes from the main, user input. Same for 'in', fullfilled before by the user.

FYI in java you don't need to initialize arrays to zeroes; that is guaranteed. — Bohemian, Aug 19 '15 at 18:34

score 0 · Answer 1 · answered Aug 19 '15 at 18:36

0

Have you considered using a LinkedList? This internally manages the array so you don't need to deal with moving the elements yourself; you can just call remove().

answered Aug 19 '15 at 18:36

Keith

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I did, and it works! Tho, I'm doing this as an exercise from a school textbook, so I'm not allowed to use it. – Monok Aug 19 '15 at 18:42

score 0 · Accepted Answer · answered Aug 19 '15 at 18:38

You will have to iterate over the array two times: The first time, you count how often v is contained in in. If count is 0, you can return in, otherwise you would have to create a new array of length in.length - count. Then again you have to iterate over in and add every value that is not v to your Array.

int count = 0;

    for(int i: in) {
        if (i==v) {
            count++;
        }
    }

    int[] result = new int[in.length-count];
    int pos=0;
    for(int i: in) {
        if (i!=v) {
            result[pos] = i;
            pos++;
        }
    }

But you could use Collections to make it easier:

public static void main(String[] args) {
    int v = 2;
    int[] in = new int[]{1, 2, 3, 4, 5};

    List<Integer> list = new ArrayList<>();
    for(int i: in) {
        if (i!=v) {
            list.add(i);
        }
    }

    Integer[] result = list.toArray(new Integer[]{});
}

The disadvantage of this, however, would be that you have an Array of Integer and not of int.

Thanks! I didn't think about that! But can you explain me with a code example the part 'Then again you have to iterate over in and add every value that is not v to your Array.'? — Monok, Aug 19 '15 at 18:43
Ok, now I got it! Thank you very much, now the output is the right one! — Monok, Aug 19 '15 at 18:49

How to shift array elements after removing one?

2 Answers2