A multidimensional array in Java is an array of arrays. This means that each element of a multidimensional array is an array itself. Multidimensional arrays can be used to store data in a variety of different ways, such as:
Storing a table of data
Storing a list of lists
Storing a tree of data
Storing a grid of data
To declare a multidimensional array, you use the following syntax:
Multidimensional Array<data_type>[][] <array_name>;
For example, to declare a two-dimensional array of integers, you would use the following syntax:
2D Array
int[][] myArray;
This will create an uninitialized two-dimensional array of integers. To initialize the array, you can use the following syntax:
2D array initialization
int[][] myArray = {{1, 2, 3}, {4, 5, 6}};
This will create a two-dimensional array of integers with the values 1, 2, 3, 4, 5, and 6.
Accessing elements in a multidimensional array
To access an element in a multidimensional array, you use the following syntax:
Accessing 2D array
<array_name>[<index1>][<index2>]
The index1 is the index of the outer array and the index2 is the index of the inner array. The first index of the outer array is 0 and the first index of the inner array is 0.
For example, to access the second element in the second row of the array myArray, you would use the following syntax:
Accessing elements in 2D array
myArray[1][1]
This will return the value 5.
Iterating over a multidimensional array
There are two ways to iterate over a multidimensional array:
Nested for loops: You can use nested for loops to iterate over the elements of a multidimensional array. The following syntax shows how to use nested for loops to iterate over the elements of a multidimensional array:
2D Array iteration using for loops
for (int i = 0; i < <array_name>.length; i++) {
for (int j = 0; j < <array_name>[i].length; j++) {
// Code to execute for each element in the multidimensional array
}
}
Enhanced for loops: You can use enhanced for loops to iterate over the elements of a multidimensional array. The following syntax shows how to use enhanced for loops to iterate over the elements of a multidimensional array:
2D Array iteration using for-each loops
for (int[] element : <array_name>) {
for (int value : element) {
// Code to execute for each element in the multidimensional array
}
}
Summary
Multidimensional arrays are a powerful data structure that can be used to store and manipulate collections of data in a variety of different ways. Multidimensional arrays are easy to use and can be used to implement a variety of different algorithms.
Here are some additional things to keep in mind when using multidimensional arrays in Java:
Multidimensional arrays can be of any number of dimensions.
Multidimensional arrays can be heterogeneous. This means that the elements of a multidimensional array can be of different data types.
Multidimensional arrays can be passed to methods and stored in variables.
Tutorialsbox