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修改项目目录

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seahi
2024-10-09 11:06:06 +08:00
parent 028ae17647
commit a3e84dc516
29 changed files with 457 additions and 17 deletions
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32
src/chapter2/ClassScoreAnalyzer.java Normal file
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package chapter2;
public class ClassScoreAnalyzer {
public static void main(String[] args) {
// 1. 创建并初始化数组
int[] testScores = {85, 92, 78, 95, 88};
// 2. 使用循环打印所有学生的成绩
for (int i = 0; i < testScores.length; i++) {
System.out.println("学生" + (i + 1) + "的成绩：" + testScores[i]);
}
// 4. 调用 findHighestScore 方法并打印结果
int highestScore = findHighestScore(testScores);
System.out.println("班级最高分是：" + highestScore);
}
// 3. 编写 findHighestScore 方法
public static int findHighestScore(int[] scores) {
if (scores == null || scores.length == 0) {
return -1; // 返回-1表示数组为空或null
}
int max = scores[0]; // 假设第一个元素是最大的
for (int i = 1; i < scores.length; i++) {
if (scores[i] > max) {
max = scores[i];
}
}
return max;
}
}

40
src/chapter2/Department.java Normal file
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package chapter2;
import java.util.Scanner;
public class Department {
/*
* 根据用户输入的信息确定员工应分配到那个部门。
*/
public static void main(String[] args) {
// 声明一个 Scanner 对象，用来读取用户的输入
Scanner input = new Scanner(System.in);
System.out.println("请输入员工的姓名");
String name = input.nextLine();
System.out.println("请输入新员工应聘的语言：");
String language = input.nextLine();
switch (language) {
case "java":
case "Java":
System.out.println(name + " 被分配到Java程序开发部门");
break;
case "C#":
case "c#":
System.out.println(name + " 被分配到C#程序开发部门");
break;
case "asp.net":
System.out.println(name + "被分配到asp.net程序测试");
break;
case "html":
case "HTML":
System.out.println(name + "被分配到前端程序开发部门");
break;
default:
System.out.println("抱歉，本公司不需要" + language + "语言的人");
break;
}
}
}

12
src/chapter2/Example07.java Normal file
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package chapter2;
public class Example07 {
public static void main(String[] args) {
int x = 5;
if (x < 10) {
x ++; // x = x + 1;
}
System.out.println("x=" + x);
}
}

13
src/chapter2/Example08.java Normal file
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package chapter2;
public class Example08 {
public static void main(String[] args) {
int num = 20;
if (num % 2 == 0) {
System.out.println("num是一个偶数");
} else {
System.out.println("num是一个奇数");
}
}
}

16
src/chapter2/Example09.java Normal file
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package chapter2;
public class Example09 {
public static void main(String[] args) {
int grade = 75;
if (grade > 80) {
System.out.println("该成绩的等级为优");
} else if (grade > 70) {
System.out.println("该成绩的等级是良");
} else if (grade > 60) {
System.out.println("该成绩的等级是中");
} else {
System.out.println("该成绩的等级是差");
}
}
}

13
src/chapter2/Example10.java Normal file
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package chapter2;
public class Example10 {
public static void main(String[] args) {
int x = 0;
int y = 10;
int max;
max = x > y ? 100 : 1000;
System.out.println("max=" + max);
}
}

33
src/chapter2/Example11.java Normal file
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package chapter2;
public class Example11 {
public static void main(String[] args) {
int week = 1;
switch (week) {
case 1:
System.out.println("星期一");
break;
case 2:
System.out.println("星期二");
break;
case 3:
System.out.println("星期三");
break;
case 4:
System.out.println("星期四");
break;
case 5:
System.out.println("星期五");
break;
case 6:
System.out.println("星期六");
break;
case 7:
System.out.println("星期日");
break;
default:
System.out.println("数值错误");
}
}
}

11
src/chapter2/Example12.java Normal file
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package chapter2;
public class Example12 {
public static void main(String[] args) {
int x = 5; // 定义变量x，初始值为1
while (x <= 4) { // // 循环条件
System.out.println("x = " + x); // 条件成立，打印x的值
x ++; // x进行自增
}
}
}

11
src/chapter2/Example13.java Normal file
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package chapter2;
public class Example13 {
public static void main(String[] args) {
int x = 5;
do {
System.out.println("x = " + x);
x ++;
} while (x <= 4);
}
}

11
src/chapter2/Example14.java Normal file
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package chapter2;
public class Example14 {
public static void main(String[] args) {
int sum = 0;
for (int i = 1; i <= 4; i++) {
sum += i;
}
System.out.println("sum = " + sum);
}
}

14
src/chapter2/Example16.java Normal file
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package chapter2;
public class Example16 {
public static void main(String[] args) {
int x = 1;
while (x <= 4) {
System.out.println("x = " + x);
if (x == 3) {
continue;
}
x ++;
}
}
}

14
src/chapter2/Example17.java Normal file
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package chapter2;
public class Example17 {
public static void main(String[] args) {
int x = 1;
while (x <= 4) {
System.out.println("x = " + x);
if (x == 3) {
continue;
}
x ++;
}
}
}

18
src/chapter2/Example19.java Normal file
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package chapter2;
public class Example19 {
public static void main(String[] args) {
printRectangle(3, 5);
}
// 下面定义了一个打印矩形的方法，接收两个参数，其中height为高，width为宽
public static void printRectangle(int height, int width) {
// 下面是使用嵌套for循环实现*打印矩形
for (int i = 0; i < height; i++) {
for (int j = 0; j < width; j++) {
}
}
}
}

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src/chapter2/Example20.java Normal file
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package chapter2;
public class Example20 {
public static void main(String[] args) {
int area = getArea(3, 5);
System.out.println("The area is " + area);
}
public static int getArea(int x, int y) {
int temp = x * y;
return temp;
}
}

29
src/chapter2/Example21.java Normal file
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package chapter2;
public class Example21 {
public static void main(String[] args) {
// 下面针对求和方法的调用
int sum1 = add(1, 2);
int sum2 = add(2, 2, 3);
double sum3 = add(1.2, 2.3);
// 下面的代码是打印求和的结果
System.out.println("sum1 = " + sum1);
System.out.println("sum2 = " + sum2);
System.out.println("sum3 = " + sum3);
}
// 下面的方法实现了两个整数相加
public static int add(int a, int b) {
return a + b;
}
// 下面的方法实现了三个整数相加
public static int add(int a, int b, int c) {
return a + b + c;
}
// 下面的方法实现了两个小数相加
public static double add(double a, double b) {
return a + b;
}
}

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src/chapter2/Example22.java Normal file
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package chapter2;
public class Example22 {
public static void main(String[] args) {
int[] arr; // 声明变量
arr = new int[3]; // 创建数据对象
System.out.println("arr[0] = " + arr[0]); // 访问数组中的第一个元素
System.out.println("arr[1] = " + arr[1]); // 访问数组中的第二个元素
System.out.println("arr[2] = " + arr[2]); // 访问数组中的第三个元素
System.out.println("数组的长度是：" + arr.length); // 打印数组的长度
}
}

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src/chapter2/Example23.java Normal file
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package chapter2;
public class Example23 {
public static void main(String[] args) {
int[] arr = new int[4]; // 定义可以存储4个元素的整数类型数组
arr[0] = 1; // 为第1个元素赋值1
arr[1] = 1; // 为第2个元素赋值2
//依次打印数组中每个元素的值
System.out.println("arr[0]: " + arr[0]);
System.out.println("arr[1]: " + arr[1]);
System.out.println("arr[2]: " + arr[2]);
System.out.println("arr[3]: " + arr[3]);
}
}

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src/chapter2/GetMax.java Normal file
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package chapter2;
public class GetMax {
public static void main(String[] args) {
}
}

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src/chapter2/SuperMarket.java Normal file
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package chapter2;
import java.util.Scanner;
public class SuperMarket {
/*
* 模拟商城购物小系统：
* 1.用户选择商品后，后台计算商品价格；
* 2.使用while循环实现用户多次购买商品。
*/
public static void main(String[] args) {
double cup = 18.8; //水杯价格
double apple = 12.5; //苹果价格
double banana = 15.5; //香蕉价格
int i = 0; // 用户购买的商品序列
String continueShopping = "Y"; // 是否继续购物
System.out.println("==============天津现代小卖部================");
System.out.println("1.水杯的价格为：" + cup + "元");
System.out.println("2.苹果的价格为：" + apple + "元");
System.out.println("3.香蕉的价格为：" + banana + "元");
while (continueShopping.equals("Y")) {
Scanner sc1 = new Scanner(System.in);
System.out.println("请输入你需要购买商品的序列号：");
i = sc1.nextInt();
switch (i) {
case 1:
System.out.println("请输入你需要购买水杯的数量:");
int cupnumber = sc1.nextInt();
double cupnum = cupnumber * cup;
System.out.println("你购买了水杯" + cupnumber + "个，需要花费" + cupnum + "元");
break;
case 2:
System.out.println("请输入你需要购买苹果的数量:");
int applenumber = sc1.nextInt();
double applenum = applenumber * apple;
System.out.println("你购买了苹果" + applenumber + "斤，需要花费" + applenum + "元");
break;
case 3:
System.out.println("请输入你需要购买香蕉的数量:");
int banananumber = sc1.nextInt();
double banananum = banananumber * banana;
System.out.println("你购买了香蕉" + banananumber + "斤，需要花费" + banananum + "元");
break;
}
System.out.println("需要继续购买请输入Y，否则输入N");
continueShopping = sc1.next();
}
System.out.println("期待您的下次光临！");
}
}

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src/chapter2/User.java Normal file
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package chapter2;
import java.util.Scanner;
public class User {
// 存储用户名和密码
// 两个数组前加上static属性，这样做是为了让本类都可以使用到这两个数组
static String[] usernames = new String[10];
static String[] passwords = new String[10];
static int count = 1;
public static void main(String[] args) {
// 假设系统中已经有一个用户
usernames[0] = "java";
passwords[0] = "123456";
while (true) {
print();
Scanner input = new Scanner(System.in);
System.out.println("请选择功能：");
int option = input.nextInt();
switch (option) {
case 0:
System.exit(0);
case 1:
login();
break;
case 2:
register();
break;
case 3:
show();
break;
default:
System.out.println("输入错误！");
break;
}
}
}
/*
* 登录功能，键盘输入用户名与密码
* 使用for循环加if判断验证输入的用户名与密码是否正确
*/
public static void login() {
Scanner input = new Scanner(System.in);
System.out.println("请输入用户名：");
String username = input.next();
System.out.println("请输入密码：");
String password = input.next();
for (int i = 0; i < count; i++) {
if (username.equals(usernames[i]) && password.equals(passwords[i])) {
System.out.println("登录成功！");
return;
}
}
System.out.println("登录失败，请重新输入");
}
/*
* 注册功能
* 定义一个boolean变量，使用for循序判断用户是否存在
* 如果用户不存在，在数组中插入注册的账号密码时
* 可能会有数组长度不够的情况，所以需要使用到
* 增加数组的长度，这里调用增加数组长度的方法add()。
*/
public static void register() {
Scanner input = new Scanner(System.in);
System.out.println("请输入用户名：");
String username = input.next();
System.out.println("请输入密码：");
String password = input.next();
boolean flag = true;
for (int i = 0; i < count; i++) {
if (username.equals(usernames[i])) {
System.out.println("用户名已存在");
flag = false;
}
}
if (flag) {
if (count < usernames.length) {
count++;
usernames[count - 1] = username;
passwords[count - 1] = password;
System.out.println("注册成功！");
} else {
System.out.println("数组空间不足！");
}
}
}
/*
* 查看功能
*/
public static void show() {
for (int i = 0; i < count; i++) {
System.out.println("用户名：" + usernames[i] + "，密码：" + passwords[i]);
}
}
/*
* 打印功能菜单
*/
public static void print() {
System.out.println("-----------------用户管理系统-------------------");
System.out.println("1.登录功能");
System.out.println("2.注册功能");
System.out.println("3.查看");
System.out.println("0.退出");
System.out.println("-----------------用户管理系统-------------------");
}
}