源码，求大神指点指点哪里还能改进

Question

主页面设计public class Mainpage2 { Scanner sure = new Scanner(System.in); int[] cunchu = new int[20];int ave; int sum = 0; // 总价 int sum2; int Cunchu; String newString = new String(); RentMoney rentMoney = new RentMoney(); Car menu = new Car(); Rent rent = new Rent(); String[] string = new String[10]; public Mainpage2() { System.out.println("*******您是否是要使用嗒嗒租车系统(1/Y,0/N)********"); int choose1 = sure.nextInt(); if (choose1 == 1) { System.out.println("您可选择的车辆和价目如下:"); System.out.println("  序号          租金（RMB）   容量"); System.out.println("1.奥迪A4    200/天           载人：4人"); System.out.println("2.宝马3系     400/天           载人：4人"); System.out.println("3.马自达       100/天           载人：4人"); System.out.println("4.福特F-150 200/天           载人：4人 载货:20t"); System.out.println("5.金龙          800/天           载货:4t"); System.out.println("6.松花江      1000/天          载货:4t"); System.out.println("请输入您需要租借的车辆数："); mainpage(); } else { System.out.println("您已退出系统!"); System.exit(0); } } public void mainpage() { int choose2 = sure.nextInt(); // 租车的数量 int choose3; // 租车的序号 for (int i = 1; i <= choose2; i++) { System.out.println("请输入第" + i + "辆车子的序号"); choose3 = sure.nextInt(); cunchu[i - 1] = choose3;                               // 将租车序号保存到数组中 }                                                          // 定义一个类，存储每类车的价钱 System.out.println("请输入您需要租车的天数"); int choose = sure.nextInt();  for (int u = 0; u < choose2; u++) {                        //调用RentMoney(租金类) Cunchu = cunchu[u]; ave = rentMoney.character(Cunchu); sum += rent.jisuan(choose, ave); } for (int t = 0; t < choose2; t++) {                        //调用Car(车名)，将用户已选择的租车车名存入数组 Cunchu = cunchu[t]; string[t] = menu.car(Cunchu); } System.out.println("您所选择的车子有："); for (int x = 0; x < choose2; x++) { newString = string[x]; System.out.println("    " + newString); } System.out.println("一共租" + choose + "天，是否确定(1/Y,0/N)"); int choose5 = sure.nextInt(); if (choose5 == 1) { System.out.println("您需要支付：" + sum); } else { System.out.println("请重新选择"); mainpage(); }}}2.租金类public class RentMoney { public int character(int x) { int y = 0; switch (x) { case 1: y = 200; break; case 2: y = 400; break; case 3: y = 100; break; case 4: y = 200; break; case 5: y = 800; break; case 6: y = 1000; break; default: System.out.println("输入错误"); break; } return y; }3.车名类public class Car { public String car(int x) { String string = new String(); switch (x) { case 1: string = "奥迪A4"; break; case 2: string = "宝马3系"; break; case 3: string = "马自达"; break; case 4: string = "福特F150"; break; case 5: string = "东风马自达"; break; case 6: string = "松花江"; break; default: break; } return string;}}4.计算租金public class Rent { int sum; int q, p; public int jisuan(int x, int y) { return sum = x * y; }}

Answer 1

对于输入1/0，没有判断输入其他数字时的情况而一味归为0，显得代码不够严谨