1.数组的相关注意事项

错误示范一

String strs[] = new String[2]{"a", "b"};

正确示范一

String strs[] = new String[]{"a", "b"};

 让JVM自己判断有几个数据，无需再其中写明有几组数据

错误示范二

String strs[] = new String{"a", "b"};

正确示范二

String strs[] = {"a", "b"};

2.数组相关练习

/*
已知有个升序数组，要求插入一个元素，该数组顺序依然是升序的
*/
import java.util.Scanner;
public class ArrayHomework01 {public static void main(String[] args) {Scanner myScanner = new Scanner(System.in);int arr[] = {10, 12, 45, 90};int arr2[] = new int[arr.length + 1];System.out.println("请输入你要添加的数字");int addNum = myScanner.nextInt();for (int j = 0; j < arr.length; j++) {//直接扩容arr2[j] = arr[j];arr2[j+1] = addNum;}arr = arr2;//将原数组地址定位到扩容后的数组的地址int temp = 0;for (int i = 0; i < arr.length; i++) {//再用冒泡算法重新排列int times = arr.length - 1;for (int j = 0; j < times; j++) {if (arr[j] > arr[j+1]) {temp = arr[j];arr[j] = arr[j+1];arr[j+1] = temp;}}}for (int i = 0; i < arr.length; i++) {//输出排列完后的数组System.out.print(arr[i] + " ");}}
}

//解法2
public class ArrayHomework01 {public static void main(String[] args) {int arr[] = {10, 12, 45, 90};int insertNum = 23;int index = -1;for (int i = 0; i < arr.length; i++) {if (insertNum <= arr[i]) {index = i;break;} } if (index == -1) {index = arr.length;}//System.out.print(index);int arrNew[] = new int[arr.length + 1];for (int i = 0, j = 0; i < arrNew.length; i++) {if (i != index) {arrNew[i] = arr[j];j++;} else {arrNew[i] = insertNum;}}arr = arrNew;for (int i = 0; i < arr.length; i++) {System.out.print(arr[i] + " ");}}
}