In Java, an array is a collection of similar types of elements that are stored in a contiguous block of memory. Here are some basics of arrays in Java:
1. Declaration: To declare an array in Java, you specify the type of elements it will hold, followed by the array name and the size of the array in square brackets. For example:
int[] numbers = new int[10];
This declares an array called `numbers` that can hold 10 integer values.
2. Initialization: Once an array is declared, you can initialize its elements with values using an index. Array indices in Java start at 0. For example:
numbers[0] = 1; numbers[1] = 2; // ... numbers[9] = 10;
This initializes the elements of the `numbers` array with values 1 through 10.
Alternatively, you can declare and initialize an array in one step, like this:
int[] numbers = {1, 2, 3, 4, 5};
This creates an array called `numbers` and initializes its elements with the values 1 through 5.
3. Accessing elements: You can access the elements of an array using an index. For example:
int x = numbers[2]; // x is 3
This assigns the value 3, which is the third element of the `numbers` array, to the variable `x`.
4. Length: You can get the length of an array using the `length` property. For example:
int size = numbers.length; // size is 5
This assigns the value 5, which is the length of the `numbers` array, to the variable `size`.
5. Multidimensional arrays: Java also supports multidimensional arrays, which are arrays of arrays. For example:
int[][] matrix = {{1, 2}, {3, 4}, {5, 6}};
This creates a 3×2 matrix of integers.
Arrays are widely used in Java programming to store collections of data in a structured way. They can be used to simplify code and make it more efficient.