Arrays and Array Lists - Java Concepts - page 426

int[][] b = new int[5][];

Then allocate each row separately.

for (int i = 0; i < b.length; i++)
b[i] = new int[i + 1];

You can access each array element as b[i][j] , but be careful that j is less than
b[i].length .

Naturally, such Ȓraggedȓ arrays are not very common.

A DVANCED T OPIC 7.3: Multidimensional Arrays

You can declare arrays with more than two dimensions. For example, here is a
three-dimensional array:

int[][][] rubiksCube = new int[3][3][3];

Each array element is specified by three index values,

rubiksCube[i][j][k]

However, these arrays are quite rare, particularly in object-oriented programs, and
we will not consider them further.

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7.7 Copying Arrays

Array variables work just like object variablesȌthey hold a reference to the actual
array. If you copy the reference, you get another reference to the same array (see
Figure 7 ):

An array variable stores a reference to the array. Copying the variable yields a
second reference to the same array.

double[] data = new double[10];
. . . // Fill array
double[] prices = data;

If you want to make a true copy of an array, call the clone method (see Figure 8 ).