多维数组

package array;

public class ArrayDemo05 {
    public static void main(String[] args) {

        //[4][2]   面向对象
        /*
              1,2   array[0]
              2,3   array[1]
              3,4   array[2]
              4,5   array[3]
         */
        int[][] array = {{1,2},{2,3},{3,4},{4,5}};

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

        }

    }
    //打印数组元素
    public static void prinArray(int[]arrays){
        for (int i = 0; i <arrays.length; i++) {
            System.out.println(arrays[i]+" ");
        }
    }



}

Arrays类讲解

package array;

import java.util.Arrays;

public class ArrayDemo06 {
    public static void main(String[] args) {

        int[] a = {1, 2, 3, 4, 9090, 31231, 541, 3131};


        //System.out.println(a);//[I@4554617c
        //打印数组元素Arrays.toString
        //System.out.println(Arrays.toString(a));

        Arrays.sort(a);//数组进行排序:升序

        System.out.println(Arrays.toString(a));

        Arrays.fill(a,0);//数组填充
        System.out.println((Arrays.toString(a)));
        
    }

    //重复造轮子
    public static void printArray(int[] a) {
        for (int i = 0; i < a.length; i++) {
            if (i == 0) {
                System.out.print("[");
            }
            if (i == a.length-1) {
                System.out.print(a[i] + "]");
            } else {
                System.out.print(a[i] + ",");
            }
        }
    }
}