How do I fill a String array in one method with data from another?

Question

After meddling with arrays and countless google searches, I can't seem to find the answer.

    public static void main(String args[]){
        String[] names = new String[4]; //I want to fill this up with data from country
        country(names);
        System.out.println(names(0)) //I want this to display Madrid
    }

    public static void country(String[] names){
        names[0] = "Madrid"; 
        names[1] = "Berlin";
        return;
    }

I'm not sure if this explains what I'm trying to do.

@ElliottFrisch also, wouldn't that give a compiler-error since he uses () instead of [] to access the 0-th array element? — nem035
– nem035, Commented Oct 3, 2014 at 23:02
Sorry my mind seemed to go blank, I didnt actually notice that. It did work as intended after changing the few mistakes. — Fulgurite
– Fulgurite, Commented Oct 3, 2014 at 23:05
@nem Good catch, I'd just use System.out.println(Arrays.toString(names)); — Elliott Frisch
– Elliott Frisch, Commented Oct 3, 2014 at 23:05

EBoulben · Accepted Answer · 2014-10-03 23:05:21Z

2

You really have to work on java syntax. Your code is quite simple so it should work immediately, but you have to be careful with some details, here is a code which works fine:

public static void main(String args[]) {
    String[] names = new String[4]; //I want to fill this up with data from country
    country(names);
    System.out.println(names[0]); //I want this to display Madrid
}

public static void country(String[] names) {
    names[0] = "Madrid";
    names[1] = "Berlin";
}

As you can see I use [ ] to access a value at a specific index in an array. I don't use any return in a void method neither.

You don't need to return the array in country method because java don't pass arguments on value (see http://javarevisited.blogspot.fr/2012/12/does-java-pass-by-value-or-pass-by-reference.html)

So I really advice you to read any tutorial you can find about java syntax to improve yourself for now.

answered Oct 3, 2014 at 23:05

EBoulben

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2 Comments

Fulgurite Over a year ago

Yeah I just started leaning java last week. I didn't notice the silly mistakes I was making until the comments pointed it out.

EBoulben Over a year ago

that's normal when you start. I don't know any good english tutorial for beginning java, but I'm sure there are some posts about it in this forum ;) Java is fun, keep going ! And use a good IDE (lot of choice, my favorite are eclipse (open source) and IntelliJ (there is a free version)), it would have inform you there was syntax mistake, there message can be very helpful, like nem said it in comment from your question.

nem035 · Accepted Answer · 2014-10-03 23:11:15Z

1

Arrays are accessed using [], not (). You are also missing a semicolon in the printing statement.

Change:

System.out.println(names(0))

To:

System.out.println(names[0]);  // use [] instead of () and add a semicolon

Also, the method country(String[] names) returns void so you don't need the return statement at the end of it (it's implied).

Here's how your code should look like:

   public static void main(String args[]){
        String[] names = new String[4]; //I want to fill this up with data from country
        country(names);
        System.out.println(names[0]); // use [] instead of () and add a semicolon
    }

    public static void country(String[] names){
        names[0] = "Madrid"; 
        names[1] = "Berlin";
    }

edited Oct 3, 2014 at 23:11

answered Oct 3, 2014 at 22:59

nem035

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