好久没更新了，最近学了Java语言，下面简单写个项目-零钱通：
化繁为简： 1. 先完成显示菜单，并可以选择菜单，给出对应显示 2. 完成零钱通明细 3. 完成收益入账 4. 消费 5. 退出 6. 代码优化 方法1（面向过程）：
package SmallChangeSys;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Scanner;
public class SmallChangeSys {
public static void main(String[] args) {
boolean loop = true;
double money = 0;
double balance = 0;
String note = "";
String choice = "";
Date date = new Date();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm");
Scanner scanner = new Scanner(System.in);
String key = "";
String detail = "---------------零钱通明细--------------";
do{
System.out.println("\n--------------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\t1" + "4 退 出");
System.out.print("请选择（1-4）：");
key = scanner.next();
//菜单
switch(key) {
case "1":
System.out.println(detail);
break;
case "2":
System.out.print("请输入入账的金额：");
money = scanner.nextDouble();
if(money <= 0) {
System.out.println("你的入账金额应该在 大于 0");
break;
}
balance += money;
detail += "\n收益入账\t+" + money + "\t" + sdf.format(date) +
"\t余额:" + balance;
break;
case "3":
System.out.print("输入消费项目:");
note = scanner.next();
System.out.print("输入消费金额:");
money = scanner.nextDouble();
if(money <= 0 || money > balance) {
System.out.println("你的消费金额 应该在 0-" + balance);
break;
}
balance -= money;
detail += "\n"+ note + "\t-" + money + "\t" + sdf.format(date) +
"\t余额:" + balance;
break;
case "4":
System.out.print("您是否要退出");
while(true) {
System.out.print("\t输入（y/n）:");
choice = scanner.next();
if(choice.equals("y") || choice.equals(("n"))) {
break;
}
}
if(choice.equals("y")) {
loop = false;
}
break;
}
}while(loop);
System.out.println("退出了零钱菜单");
}
}
方法2（面向对象-OOP）：
package OOP;
//main类
public class SmallChangeSysApp {
public static void main(String[] args) {
new SmallChangeSysOOP().mainMenu();
}
}
//菜单类
package OOP;
package OOP;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Scanner;
public class SmallChangeSysOOP {
boolean loop = true;
double money = 0;
double balance = 0;
String note = "";
String choice = "";
Date date = new Date();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm");
Scanner scanner = new Scanner(System.in);
String key = "";
String detail = "---------------零钱通明细--------------";
public void mainMenu() {
do{
System.out.println("\n--------------选择零钱通菜单--------------");
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\t1" + "4 退 出");
System.out.print("请选择（1-4）：");
key = scanner.next();
//菜单
switch(key) {
case "1":
this.detail();
break;
case "2":
this.income();
break;
case "3":
this.pay();
break;
case "4":
this.exit();
break;
}
}while(loop);
System.out.println("退出了零钱菜单");
}
public void detail() {
System.out.println(detail);
return;
}
public void income() {
System.out.print("请输入入账的金额：");
money = scanner.nextDouble();
if(money <= 0) {
System.out.println("你的入账金额应该在 大于 0");
return; //返回方法
}
balance += money;
detail += "\n收益入账\t+" + money + "\t" + sdf.format(date) +
"\t余额:" + balance;
return;
}
public void pay() {
System.out.print("输入消费项目:");
note = scanner.next();
System.out.print("输入消费金额:");
money = scanner.nextDouble();
if(money <= 0 || money > balance) {
System.out.println("你的消费金额 应该在 0-" + balance);
return;
}
balance -= money;
detail += "\n"+ note + "\t-" + money + "\t" + sdf.format(date) +
"\t余额:" + balance;
return;
}
public void exit() {
System.out.print("您是否要退出");
while(true) {
System.out.print("\t输入（y/n）:");
choice = scanner.next();
if(choice.equals("y") || choice.equals(("n"))) {
break;
}
}
if(choice.equals("y")) {
loop = false;
}
return;
}
}
目标大厂，冲冲冲！！