Lesson 14 / 38

Arrays

Create fixed-size 1-D and 2-D arrays, access elements safely within bounds, and use java.util.Arrays for sort, fill, copyOf and toString.

Create & access

An array has a fixed length set at creation. Indexes are 0..length-1; going outside throws ArrayIndexOutOfBoundsException.

int[] a = new int[3];        // {0, 0, 0}
int[] b = {10, 20, 30};
b[1] = 99;
System.out.println(b.length); // 3

int[][] grid = new int[2][2]; // 2-D

java.util.Arrays

The Arrays class has helpers: sort, fill, copyOf, equals, and toString (plain println on an array prints its hash-like form).

int[] a = {3, 1, 2};
Arrays.sort(a);
System.out.println(Arrays.toString(a)); // [1, 2, 3]