328讲 断点调试（debug）、断点调试案例、零钱通案例。

零钱通

• 面向过程

package main.smallChange;
//面向过程编程
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Scanner;

public class SmallChangeSys {
    public static void main(String[] args) {
        //打印零钱通菜单
        //循环打印菜单表，直到选择退出
        Scanner myScanner = new Scanner(System.in);
        boolean loop = true;

        double balance = 0;
        double income = 0;
        double consume = 0;
        Date date = new Date();//获取时间
        SimpleDateFormat sdf = new SimpleDateFormat("YYYY-MM-DD HH:MM");
        String detail = "-------零钱通明细-----";
        do {
            System.out.println("===========零钱通=========");
            System.out.println("\t\t\t1 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.println("请选择1-4:");
            int num = myScanner.nextInt();

            switch (num) {
                case 1:
                    System.out.println(detail);
                    System.out.println();
                    break;
                case 2:
                    System.out.println("---收益入账---");
                    System.out.println("输入收益入账金额：");
                    income = myScanner.nextDouble();
                    if(income <= 0){
                        System.out.println("收益金额要>0");
                        break;
                    }
                    balance += income; //计算余额。
                    detail += "\n收益入账\t" + income + " \t\t" + sdf.format(date) +
                            "\t余额\t" + balance;
                    break;
                case 3:
                    System.out.println("----消费----");
                    System.out.println("请输入消费金额");
                    consume = myScanner.nextDouble();
                    if(consume <= 0 || consume > balance){
                        System.out.println("消费金额要大于0且小于余额"+ balance);
                        break;
                    }
                    System.out.println("请输入消费类型");
                    balance -= consume;//减去消费的金额;
                    detail += "\n" + myScanner.next() + "\t-" +
                            consume + "\t" + sdf.format(date) + "\t余额\t" + balance;
                    break;
                case 4:
                    String str = "";
                    while (true) {
                        System.out.println("确定要退出吗？y/n");
                        str = myScanner.next();
                        if ("y".equals(str) || "n".equals(str)) {
                            break;
                        }
                    }
                    if (str.equals("y")) {
                        loop = false;

                    }
                    break;
                default:
                    System.out.println("你输入的有误，请输入1-4");
            }
        } while (loop);
        //打印零钱通内部的表
    }
}

• 面向对象 OPP

SmallChangeSysOOP各个功能的类 SmallChangeStsApp调用类

package main.smallChangeSysOOP;

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

public class SmallChangeSysOOP {
        //打印零钱通菜单
        //循环打印菜单表，直到选择退出
        Scanner myScanner = new Scanner(System.in);
        boolean loop = true;

        double balance = 0;
        double income = 0;
        double consume = 0;
        Date date = new Date();//获取时间
        SimpleDateFormat sdf = new SimpleDateFormat("YYYY-MM-DD HH:MM");
        String detail = "-------零钱通明细-----";

        public void getManue(){
            do{
                System.out.println("===========零钱通=========");
                System.out.println("\t\t\t1 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.println("请选择1-4:");
                int num = myScanner.nextInt();
                switch (num){
                    case 1:
                        getDetail();
                        break;
                    case 2:
                        getIncome();
                        break;
                    case 3:
                        getConsume();
                        break;
                    case 4:
                        exit();
                        break;
                    default:
                        System.out.println("输入有误，请输入1-4");
                }
            }while(loop);

        }

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

        public void getIncome(){
            System.out.println("---收益入账---");
            System.out.println("输入收益入账金额：");
            income = myScanner.nextDouble();
            if(income <= 0){
                System.out.println("收益金额要>0");
                return;
            }
            balance += income; //计算余额。
            detail += "\n收益入账\t" + income + " \t\t" + sdf.format(date) +
                    "\t余额\t" + balance;
            return;

        }

        public void getConsume(){
            System.out.println("----消费----");
            System.out.println("请输入消费金额");
            consume = myScanner.nextDouble();
            if(consume <= 0 || consume > balance){
                System.out.println("消费金额要大于0且小于余额"+ balance);
                return;
            }
            System.out.println("请输入消费类型");
            balance -= consume;//减去消费的金额;
            detail += "\n" + myScanner.next() + "\t-" +
                    consume + "\t" + sdf.format(date) + "\t余额\t" + balance;

            return;

        }

        public void exit(){
            String str = "";
            while (true) {
                System.out.println("确定要退出吗？y/n");
                str = myScanner.next();
                if ("y".equals(str) || "n".equals(str)) {
                    break;
                }
            }
            if (str.equals("y")) {
                loop = false;

            }
            return;
        }

}

package main.smallChangeSysOOP;

public class SmallChangeSysAPP {
    public static void main(String[] args) {
        SmallChangeSysOOP smallChangeSysOOP = new SmallChangeSysOOP();
        smallChangeSysOOP.getManue();
    }
}