Is it possible to swap value of two array index in java?

Question

I want to swap two values in an array but i am unable to to it. I am creating a new swap function. I know the value can only be swapped through referencing, but i don't know how to do it. Can someone please help me. Below is the code i am trying to write. I want to swap the array data in class A.

public class test { 
public static void swap(int num[],int num2,int num3) {
   //swap code
    }
public static void main(String...args) {
    A a = new A();
    A obj1 = new A();
    A obj2 = new A();
    swap(a.num,obj1.num[0],obj2.num[2]);
}}
   class A{
        int num[]={1,2,3};
     }

probably duplicate https://stackoverflow.com/questions/2393906/java-method-to-swap-primitives — Ruslan, Feb 03 '19 at 19:21
First, share your code please, we cannot help you without it — Maelig, Feb 03 '19 at 19:38

score 3 · Answer 1 · answered Feb 03 '19 at 19:18

3

int[] arr - arr is reference to the array object. Therefore you can write swap method given this reference to swap required values.

public static void swap(int[] arr, int i, int j) {
    int tmp = arr[i];
    arr[i] = arr[j];
    arr[j] = tmp;
}

answered Feb 03 '19 at 19:18

Oleg Cherednik

17,377
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score 1 · Answer 2 · answered Feb 03 '19 at 19:29

1

By the way it can be done without temporary variable:

public static void swap(int[] arr, int i, int j) {
    arr[i] ^= arr[j];
    arr[j] ^= arr[i];
    arr[i] ^= arr[j];
}

answered Feb 03 '19 at 19:29

Ruslan

6,090
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Be aware that this does not work if `i == j` (this this case `array[i]` would be set to `0`) – Clashsoft Feb 03 '19 at 19:54

Is it possible to swap value of two array index in java?

2 Answers2