9_2 two-dimensional array

Two-dimensional array is an array of two-dimensional array of each element one-dimensional array is one-dimensional array

Definition Format

1. Data Type [] [] = new Array name Data type [Several one-dimensional array] [Several one-dimensional array elements];

int [] [] arr = new int [3] [2]; // contains arr 3-dimensional array of length 2 of a two-dimensional array

public static void main(String[] argv ) {
int[][] arr= new int[2][3];
System.out.println(arr);

result:

[[I @ 15db9742 two-dimensional array of length

2. The second definition format that allows two-dimensional array of one-dimensional array length species according to their needs change, the length of each one-dimensional array can be different

Data Type [] [] = new Array name Data type [Several one-dimensional array] [];

int [] [] arr = new int [3] []; // declaration corresponds to a three-dimensional array

arr [0] = new int [2]; // this is a

arr [0] = {1,2,3}; // no open space wrong int [] arr = {1,2,3}; this is not affirmed and assignment separately