Please Explain this Java Array Reference Parameter Passing Behavior

Question

public class TestArray {
    public static void main(String[] args) {
        int[] ar = {1,2,3,4,5,6,7,8,9};

        shiftRight(ar);
        for (int i = 0; i <         


        

Answer 1

The problem is that you create a local variable temp array, and you set ar=temp. You need to actually modify the contents of ar, rather than creating a new local array and pointing your copied ar variable to temp

Try something like this.

public static void reverseArray(int[] ar) {
    int[] temp = new int[ar.length];
    System.arraycopy( ar, 0, temp, 0, ar.length );
    for (int i = 0, j = temp.length - 1; i < ar.length; i++, j--) {
        ar[i] = temp[j];
    }

    for (int i = 0; i < ar.length; i++) {
        System.out.print(ar[i]);
    }
    // prints: 876543219
    System.out.println();
}