一维数组

int[] a = {};
int[] b= new int[2];
int[] b1= new int[]{1,2};

二维数组

int[][] arr = new int[][]{{1,2,8,9},{2,4,9,12},{4,7,10,13},{6,8,11,15},{6,8,11,15}};

arr.length：行数。arr[0].length：列数

遍历方式：

for (int i = 0; i < y.length; i++) {
    for (int j = 0; j < y[i].length; j++) {
        System.out.print(y[i][j]);
        System.out.print(" ");
    }
    System.out.println();
}

• 方式一

row * column：4*3维

private static void m1() {
    int[][] arr = new int[][]{{11,12,13},{24,25,26},{41,51,61},{42,52,62}};
    for (int i = 0; i < arr.length; i++) {
        // arr[i]：第i行的元素集合
        for (int j = 0; j < arr[i].length; j++) {
            System.out.print(arr[i][j]);
            System.out.print("  ");
        }
        System.out.println();
    }
}

11  12  13  
24  25  26  
41  51  61  
42  52  62 

• 方式二

int[][] arr = new int[3][4];

• 方式三

row * column：2*3维

private static void m3() {
    int[][] arr = new int[][]{{1,2,3},{4,5,6}};
    for (int i = 0; i < arr.length; i++) {
        for (int j = 0; j < arr[i].length; j++) {
            System.out.print(arr[i][j]);
            System.out.print("  ");
        }
        System.out.println();
    }
}

1  2  3  
4  5  6