JAVA零钱通面向过程和oop

编程思想

1.每一个小功能对应一个代码块，高内聚低耦合。
2.建议先排除不正确情况，而不是对每一个正确情况做一些操作。

编程效果

源码实现

面向过程

点击查看代码

package lingqiantong.chuantong;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Scanner;

/**
 * @author LittleBear
 * @date 2024-02-09 - 14:33
 */
public class lingqiantong {
    public static void main(String[] args) {
        boolean loop = true;
        Scanner scanner = new Scanner(System.in);
        String key = "";

        String details = "-------------零钱通明细-------------";//用一个字符串来拼接所有进账/消费信息

        double money = 0;
        double balance = 0;
        Date date = null;
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm");

        String note = "";

        do {
            System.out.println("=============零钱通菜单=============");
            System.out.println("\t\t\t1 零钱通明细");
            System.out.println("\t\t\t2 收益入账");
            System.out.println("\t\t\t3 消费");
            System.out.println("\t\t\t4 退出");

            System.out.print("请选择（1-4）：");
            key = scanner.next();

            switch (key) {
                case "1":
                    System.out.println(details + "\n");
                    break;
                case "2":
                    System.out.print("入账金额：");
                    money = scanner.nextDouble();

                    if (money <= 0) {//输入金额判断,排除非正常情况
                        System.out.println("入账金额需大于0");
                        break;
                    }

                    balance += money;
                    date = new Date();
                    details += "\n收益入账\t+" + money + "\t" + simpleDateFormat.format(date) + "\t" + balance;

                    break;
                case "3":
                    System.out.print("消费：");
                    money = scanner.nextDouble();
                    if (money <= 0 || money > balance) {
                        System.out.println("你的消费金额应该在0-" + balance);
                        break;
                    }
                    System.out.print("消费说明：");
                    note = scanner.next();
                    balance = money;
                    date = new Date();
                    details += "\n" + note + "\t-" + money + "\t" +
                            simpleDateFormat.format(date) + "\t" + balance;
                    break;
                case "4":
                    String choice = "";
                    while (true) {//只允许输入y和n
                        System.out.print("你确定要退出吗(y/n):");
                        choice = scanner.next();
                        if ("y".equals(choice) || "n".equals(choice)) {
                            break;
                        }
                    }
                    if ("y".equals(choice)) {
                        loop = false;
                        break;
                    } else if ("n".equals(choice)) {
                        break;
                    }
//                    else {
//                        System.out.println("输入有误！");
//                    }//这个判断不用写，switch的穿透现象，直接用default的输出
                default:
                    System.out.println("输入有误，请重新输入！");
            }
        } while (loop);

        System.out.println("=============已退出了零钱通=============");
    }
}

面向对象

点击查看代码

package lingqiantong.oop;

/**
 * @author LittleBear
 * @date 2024-02-09 - 15:45
 */
public class app {
    public static void main(String[] args) {
        oop obj = new oop();
        obj.mianMenu();
    }
}


package lingqiantong.oop;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Scanner;

/**
 * @author LittleBear
 * @date 2024-02-09 - 15:32
 */
public class oop {
    boolean loop = true;
    Scanner scanner = new Scanner(System.in);
    String key = "";

    String details = "-------------零钱通明细-------------";
    //用一个字符串来拼接所有进账/消费信息

    double money = 0;
    double balance = 0;
    Date date = null;
    SimpleDateFormat simpleDateFormat =
            new SimpleDateFormat("yyyy-MM-dd HH:mm");

    String note = "";

    public void detail() {
        System.out.println(details);
    }

    public void income() {
        System.out.print("入账金额：");
        money = scanner.nextDouble();

        if (money <= 0) {//输入金额判断
            System.out.println("入账金额需大于0");
            return;
        }

        balance += money;
        date = new Date();
        details += "\n收益入账\t+" + money + "\t" +
                simpleDateFormat.format(date) + "\t" + balance;
    }

    public void pay() {
        System.out.print("消费：");
        money = scanner.nextDouble();
        if (money <= 0 || money > balance) {
            System.out.println("你的消费金额应该在0-" + balance);
            return;//退出方法，回到调用位置
        }
        System.out.print("消费说明：");
        note = scanner.next();
        balance = money;
        date = new Date();
        details += "\n" + note + "\t-" + money + "\t" +
                simpleDateFormat.format(date) + "\t" + balance;
    }

    public void exit() {

        String choice = "";
        while (true) {//只允许输入y和n
            System.out.print("你确定要退出吗(y/n):");
            choice = scanner.next();
            if ("y".equals(choice) || "n".equals(choice)) {
                break;
            }
        }

        if ("y".equals(choice)) {
            loop = false;
            return;
        } else if ("n".equals(choice)) {
            return;
        }
    }

    public void mianMenu() {
        do {
            System.out.println("=============零钱通菜单=============");
            System.out.println("\t\t\t1 零钱通明细");
            System.out.println("\t\t\t2 收益入账");
            System.out.println("\t\t\t3 消费");
            System.out.println("\t\t\t4 退出");

            System.out.print("请选择（1-4）：");
            key = scanner.next();

            switch (key) {
                case "1":
                    this.detail();
                    break;
                case "2":
                    this.income();
                    break;
                case "3":
                    this.pay();
                    break;
                case "4":
                    this.exit();
                    break;
                default:
                    System.out.println("输入有误！");
                    //不用写break了，到了default自动退出
                    break;
            }
        } while (loop);

        System.out.println("=============已退出了零钱通=============");
    }
}