Working with multidimensional Arrays - Java

Question

Hi working on a uni exercise and need to create a multidimensional array to hold some strings. But i'm a bit confused on how to access / declare the variables because how do i make the program know when i'm assigning variables which dimension i'm referring to? The end goal is create a 3 by 3 array but i assume the logic is the same as 2 by 2 but i just need to know how to access the arrays i want to. Thanks in advance :)

    String[][] Albums = new String[5][10];
    String song1,song2,song3;
    String album1,album2,album3;
    album1 = "Best classic hits";
    album2 = "Best pop hits";
    album3 = "Best rock hits";
    song1 = "Greatest funk song";
    song2 = "Greatest pop song";
    song3 = "Greatest rock song";
    Albums[0][0] = album1;  
    Albums[1][0] = album2;
    Albums[2][0] = album3;

Answer 1

First correct this:

// To make the size 3 by 3
String[][] Albums = new String[3][3];

Then you can access each element like this:

for(int i = 0; i < Albums.length; i++) {
    for(int j = 0; j < Albums[i].length; j++ ) {
        System.out.println(Albums[i][j]);
    }
}

Answer 2

Well you are creating a 5x10 array, you want to access the array to print the elements ? just create a nested for loop

like this

        for(i=0;i<=2;i++)
        {
            for(j=0;j<=2;j++)
            {
                System.out.print(Number[i][j]+"\t");
            }
         }

Edit reading your comment is this what you want ?

    public static void main(String[] args)
{
    String[][] Album = {
            {"Best classic hits ", "Best pop hits ", "Best rock hits "},
            {"Greatest funk song" , "Greatest pop song" , "Greatest rock song"}
    };


    System.out.println(Album[0][0] + Album[1][0]);
    System.out.println(Album[0][1] + Album[1][1]);
    System.out.println(Album[0][2] + Album[1][2]);

}

Answer 3

Start by initializing the array to the desired size. Here you said you needed 3x3, so I assume the array looks like this:

[[album, song0, song1], 
[album, song0, song1], 
[album, song0, song1]]

Because representing an object (eg (album, song0, song1) ) by array is prone to error, I would suggest creating helper methods to manage the data structure access. These methods ensure you don't override the wrong array entry by mistake.

static void setData(String[] data, String album, String song0, String song1) {
    setAlbum(data, album);
    setSong0(data, song0);
    setSong1(data, song1);
}

static String getAlbum(String[] data) {
    return data[0];
}
static void setAlbum(String[] data, String album) {
    data[0] = album;
}

static String getSong0(String[] data) {
    return data[1];
}
static void setSong0(String[] data, String song0) {
    data[1] = song0;
}

static String getSong1(String[] data) {
    return data[2];
}
static void setSong1(String[] data, String song1) {
    data[2] = song1;
}
...

String[][] data = new String[3][3];
setData(data[0], "album 0", "album 0 song 0", "album 0 song 1");
setData(data[1], "album 1", "album 1 song 0", "album 1 song 1");
setData(data[2], "album 2", "album 2 song 0", "album 2 song 1");