package com.shxt.demo01;
public class ArrayDemo02 {
public static void main(String[] args) {
int[] score = null; //声明数组,但是为开辟内存空间
score = new int[5]; //为数组开辟"堆内存"空间
for (int i = 0; i < 5; i++) {
score[i] = i*2+1;
}
for (int i = 0; i < 5; i++) {
System.out.println("score["+i+"]="+score[i]);
}
}
}
数组长度的取得
数组名称.length --> 返回一个int型的数据
package com.shxt.demo01;
public class ArrayDemo03 {
public static void main(String[] args) {
int[] score = new int[5];
System.out.println("数组长度为:"+score.length);
}
}
(3) 数组的初始化方式
动态初始化
之前练习的就是使用的动态初始化方式
package com.shxt.demo01;
public class ArrayDemo04 {
public static void main(String[] args) {
int[] score = null; //声明数组,但是为开辟内存空间
score = new int[3]; //为数组开辟"堆内存"空间
score[0] = 100;
score[1] = 200;
score[2] = 300;
}
}
静态初始化
数据类型[] 数组名={初始值0,初始值1,...,初始值N}
或者
数据类型[] 数组名 = new 数据类型[]{初始值0,初始值1,...,初始值N}
package com.shxt.demo01;
public class ArrayDemo04 {
public static void main(String[] args) {
int[] score = {10,20,30,40,50};
for (int i = 0; i < score.length; i++) {
System.out.println("score["+i+"]="+score[i]);
}
}
}
(4) 课堂练习
已知一个字符数组 char[] letterArray = new char[26] ,请动态初始化数据为A~Z
package com.shxt.demo01;
public class ArrayDemo05 {
public static void main(String[] args) {
char[] letterArray = new char[26];
for (int i = 0; i < letterArray.length; i++) {
letterArray[i] = (char)('A'+i);
}
for (int i = 0; i < letterArray.length; i++) {
System.out.print(letterArray[i]+"\t");
}
}
}
请求数组中最大和最小值
package com.shxt.demo01;
public class ArrayDemo06 {
public static void main(String[] args) {
int array[]={74,12,48,888,30,5,17,62,777,666};
int max = array[0];
int min = array[0];
for (int i = 0; i < array.length; i++) {
if(array[i]>max){
max=array[i];
}
if(array[i]<min){
min=array[i];
}
}
System.out.println("最高成绩:"+max);
System.out.println("最低成绩:"+min);
}
}
对整数数组按照由小到大的顺序进行排序
public class ArrayDemo07 {
public static void main(String[] args) {
int arr[] = {13,34,57,78,99,66,43,45,87,100};
for (int i = 0 ; i < arr.length; i++) {
for (int j = 0; j < arr.length-1; j++) {
if(arr[j]>arr[j+1]){
int temp = arr[j];
arr[j] = arr[j+1];
arr[j+1] = temp;
}
}
System.out.print("第"+i+"次 排序 的结果:\t");
for (int k = 0; k < arr.length; k++) {
System.out.print(arr[k]+"\t");
}
System.out.println();
}
System.out.print("最终的排序结果:\t");
for (int k = 0; k < arr.length; k++) {
System.out.print(arr[k]+"\t");
}
}
}
数据类型[][] 数组名 = new 数据类型[[]{{值1,值2},{值1,值2,值3...},{值1...}};
遍历二维数组
package com.shxt.demo01;
public class ArrayDemo11 {
public static void main(String[] args) {
int[][] data = new int[][]{{1,2,3},{10},{100,200}};
for (int i = 0; i < data.length; i++) { //循环行数
for (int j = 0; j < data[i].length; j++) { //循环列数
System.out.print(data[i][j]+"\t");
}
System.out.println();
}
}
}
