Why is my Java program not running?

Question

The following program swaps two elements in an array. But it does not seem to run, but I am sure that I am not doing anything wrong.

public class swap {

    public static String[] swap(int first, int second, String[] A) {
        String hold = A[first];
        A[first] = A[second];
        A[second] = hold;
        return A;
    }

    public static void main(String[] args) {
        String[] B = {"Dawn", "Justice", "Of"};
        String[] c = swap.swap(1, 2, B);
        System.out.print(c);
    }
}

It is, but your printing the arrays `toString` (or equivalent) output, not it's contents, try using `System.out.print(Arrays.toString(c));` instead — MadProgrammer, Dec 08 '15 at 03:57
@3kings The output is `[Ljava.lang.String;@2a139a55`, not what the OP is expecting (which I believe they want to see `[Dawn, Of, Justice]`) — MadProgrammer, Dec 08 '15 at 03:59
@KenSlade Thought that two, but there are 3 elements in the array and the OP wants to swap `Justice` and `of` — MadProgrammer, Dec 08 '15 at 03:59

Ankur Singhal · Accepted Answer · 2015-12-08T04:01:44.060

0

1.) Need to create Object of swap class, or since it is static no need to create object, just use swap(1, 2, B);

2.) Print Arrays.toString(c)

Modified Code

public static String[] swap(int first, int second, String[] A) {
        String hold = A[first];
        A[first] = A[second];
        A[second] = hold;
        return A;

    }

    public static void main(String[] args) {
        String[] B = { "Dawn", "Justice", "Of" };
        String[] c = swap(1, 2, B);
        System.out.print(Arrays.toString(c));

    }

output

[Dawn, Of, Justice]

edited Dec 08 '15 at 04:01

answered Dec 08 '15 at 03:59

Ankur Singhal

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Point one is void, as `swap` is `static` and doesn't rely on anything that isn't passed to it – MadProgrammer Dec 08 '15 at 04:00
@MadProgrammer yup correct, modified – Ankur Singhal Dec 08 '15 at 04:00

score -1 · Answer 2 · answered Dec 08 '15 at 04:22

import java.util.Arrays; public class swap {

public static String[] swap(int first, int second, String[] A) {
    String hold = A[first];
    A[first] = A[second];
    A[second] = hold;
    return A;
}

public static void main(String[] args) {
    String[] B = {"Dawn", "Justice", "Of"};
    String[] c = swap.swap(1, 2, B);
    System.out.print(Arrays.toString(c));
}

}

Why is my Java program not running?

2 Answers2