点击返回标题->23年Java期末复习-CSDN博客

---

第1题.

定义一个类Person,定义name和age私有属性，定义有参的构造方法对name和age进行初始化。在测试类中创建该类的2个对象，姓名、年龄分别为lili、19和lucy、20，在屏幕打印出2个对象的姓名和年龄。

 

public class Main {
    public static void main(String[] args) {
        Person p1 = new Person("lily",19);
        Person p2 = new Person("lucy",20);
        System.out.println(p1.toString());
        System.out.println(p2.toString());
    }
}
class Person{
    private String name;
    private int age;
    //有参构造给对象赋值
    Person(String name,int age){
        this.name = name;
        this.age = age;
    }
    //toString返回由name和age组成的预定字符串
    public String toString() {
        return "Person{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}

---

第2题.

首先定义一个计算长方形面积的类rectangleClass，要求类中有一个定义长方形左上角和右下角座标的构造函数，以及一个通过长方形右下角座标与左上角座标计算长方形面积,并实例化两个长方形进行测试.

 

public class Main {
    public static void main(String[] args) {
        rectangleClass rec1 = new rectangleClass(-5, 3, -3, 1);
        rectangleClass rec2 = new rectangleClass(2, -3, 4, -6);
        System.out.println("rec1" + rec1.getPoint() + "其面积为：" + rec1.getArea());
        System.out.println("rec2" + rec2.getPoint() + "其面积为：" + rec2.getArea());
    }
}
class rectangleClass {
    int x1, y1, x2, y2;
    //有参构造，定义长方形左上角和右下角座标
    rectangleClass(int x1, int y1, int x2, int y2) {
        this.x1 = x1;
        this.x2 = x2;
        this.y1 = y1;
        this.y2 = y2;
    }
    //返回计算的面积
    double getArea() {
        return Math.abs(x1 - x2) * Math.abs(y1 - y2);
    }
    //获取当前长方形左上角点和右下角点的坐标
    String getPoint() {
        return "左上角坐标为:(" + this.x1 + "," + this.y1 + ")，" + "右下角角坐标为:(" + this.x2 + "," + this.y2 + ")，";
    }
}

---

第3题.

设计一个表示图书的Book类，它包含图书的书名、作者、月销售量等私有属性，另有两个构造方法（一个不带参数，另一个带参数），成员方法setBook( ) 和printBook()分别用于设置和输出书名、作者、月销售量等数据。并设计相应的测试Book类的应用程序主类，测试并显示输出提供所有功能的结果。

 

public class Main {
    public static void main(String[] args) {
    	//b1采取有参构造实例化对象并赋值的形式
        Book b1 = new Book("三体", "刘慈欣", 114514);
        b1.printBook();
        //b2采取无参构造实例化对象，调用setBook()成员方法赋值的形式
        Book b2 = new Book();
        b2.setBook("龙族", "江南", 10086);
        b2.printBook();
    }
}
class Book {
    private String name, author;
    private int sale_volume;
    //无参构造
    Book() {
        System.out.println("无参构造被调用");
    }
    //有参构造
    Book(String name, String author, int sale_volume) {
        System.out.println("有参构造被调用");
        this.name = name;
        this.author = author;
        this.sale_volume = sale_volume;
    }
    //设置书本信息
    void setBook(String name, String author, int sale_volume) {
        this.name = name;
        this.author = author;
        this.sale_volume = sale_volume;
    }
    //打印书本信息
    void printBook() {
        System.out.printf("书名：%s    作者：%s   月销售量：%d\n", this.name, this.author, this.sale_volume);
    }
}

---

第4题.

请创建一个银行帐户类，要求如下：（１）类包括帐户名、帐户号、存款额等私有属性；（3）有三个参数的构造方法（２）可实现余额查询，存款和取款的操作。（３）创建该类的对象，验证以上两项。

 

import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        Bank b1 = new Bank("张三", "123456", 100);
        int input;
        do {//循环弹出菜单并请求选择
            menu();
            input = sc.nextInt();
            switch (input) {
                case 1:
                    b1.getBalance();
                    break;
                case 2:
                    b1.save_money();
                    break;
                case 3:
                    if(b1.getBalance()==0){
                        System.out.println("你的账户余额为0，无分文可取！");
                        break;
                    }
                    b1.withdraw_money();
                    break;
                case 0:
                    System.out.println("已退出，欢迎再次使用！");
                    break;
                default:
                    System.out.println("该选项尚未开发……");
                    break;
            }
        } while (input != 0);
    }

    public static void menu() {//打印菜单
        System.out.println("************************");
        System.out.println("****** 1.查询余额 ********");
        System.out.println("****** 2.存款    ********");
        System.out.println("****** 3.取款    ********");
        System.out.println("****** 0.退出账户 ********");
    }

    static class Bank {
        private String account_name, account_number;
        private int balance;

        public Bank(String account_name, String account_number, int balance) {
            this.account_name = account_name;
            this.account_number = account_number;
            this.balance = balance;
        }

        int getBalance() {//余额查询
            System.out.printf("用户名：%s，当前余额：%d\n", this.account_name, this.balance);
            return this.balance;
        }

        void save_money() {//存钱
            int save;
            Scanner sc = new Scanner(System.in);
            while (true) {
                System.out.println("你要存多少钱？请输入->");
                save = sc.nextInt();
                if (save <= 0) {
                    System.out.println("请输入合理的存款数！");
                    continue;
                }
                break;
            }
            this.balance += save;
            System.out.printf("完成存款，本次存款共计%d元，当前余额%d\n", save, this.balance);
        }

        void withdraw_money() {//取钱
            int withdraw;
            Scanner sc = new Scanner(System.in);
            while (true) {
                System.out.println("你要取多少钱？请输入->");
                withdraw = sc.nextInt();
                if (withdraw <= 0) {
                    System.out.println("请输入合理的取款数！");
                    continue;
                } else if (withdraw > this.balance) {
                    System.out.println("你没用这么多钱可供取款！");
                    continue;
                }
                break;
            }
            this.balance -= withdraw;
            System.out.printf("完成取款，本次取款共计%d元，当前余额%d\n", withdraw, this.balance);
        }
    }
}