java - 问 : Doing multiple loops and multiple if-statements and if-else-statements || RENTAL CAR CALCULATOR PROJECT

Question

我对该项目的说明如下:

说明:使用哨兵值循环。创建基本的租车计算器

询问每个用户:

车辆类型(可以使用字符串以外的其他内容，例如:1 表示经济型，2 表示轿车等)租用天数计算(对于每个客户):

租金成本，税收，总应付款。共有三种不同的租赁选项，价格各异:经济型 @ 31.76、轿车 @ 40.32、SUV @ 47.56。 [注意:仅考虑全天单位(无小时费率)]。

销售税 = 总额的 6%。

创建摘要数据:

客户数量收集的总金额。此外，还包括 IPO、算法和案头检查值(设计文档)。

{我要做的事情和我的问题}

package tests;

import java.util.InputMismatchException;
import java.util.Scanner;

public class Tester {

public static void main(String []args){
int count=0;
int days;
int cus = 10; 
double DailyFee=0, NontaxTotal, CarType, Total,FullTotal=0;
boolean F1 = false, F2 = false, F3 = false;
Scanner in=new Scanner(System.in);


while (F3 == false) {
    F3 = true;
    System.out.print("Press 1 to enter Rental Calculator or else press 0 to quit\n");
    System.out.println("Please only enter 1 or 0. Also, please only enter number(s) not letter(s)");
    try {
        cus=in.nextInt();
        if (cus == 0 || cus == 1) {
            F3 = true;
        } else {
            F3 = false;
            System.out.println("Number must be either 1 or 0");
        }
    } catch (InputMismatchException ex) {
        F3 = false;
        System.out.println("Invalid entry");
        in.next();
    }
}

    if(cus == 1) { 
        while(F1 == false) {
            F1 = true;
            count++;
            System.out.print("What vehical would you like to rent?\n");
            System.out.println("Enter 1 for an economy car");
            System.out.println("Enter 2 for a sedan car");
            System.out.println("Enter 3 for an SUV");
            // 
            try {
                CarType = in.nextInt();
                if (CarType <= 0 || CarType >= 4) {
                    System.out.print("Number must be 1-3\n");
                    System.out.println("Please enter 1 for an economy car");
                    System.out.println("Enter 2 for a sedan car");
                    System.out.println("Enter 3 for an SUV");

                    F1 = false;
                } else {
                     if (CarType == 1) {
                         F1 = true;
                          DailyFee=31.76;
                } else if(CarType == 2) {
                        F1 = true;
                          DailyFee=40.32;
                } else if(CarType == 3) {
                        F1 = true;
                          DailyFee=47.56;
                }
                while (F2 == false) {
                    F2 = true;
                    try { 
                        System.out.print("Please enter the number of days rented. (Example; 3) : ");
                        days = in.nextInt();
                        if (days <= 0) {
                            System.out.println("Number of days must be more than zero");
                            F2 = false;
                        } else {

                            double x=days;
                            NontaxTotal = (DailyFee * x);
                            Total = (NontaxTotal * 1.06);
                            FullTotal+=Total;
                            F3 = true;

                        }
                    } catch(InputMismatchException ex) {
                        System.out.println("Answer must be a number");
                        F2 = false;
                        in.next();
                        }
                    }
                }
            } catch (InputMismatchException ex) {
                F1 = false;
                System.out.println("Answer must be a number"); 
            }
        }
    }
    in.close();
    System.out.println("Count of customers : " + count);
    System.out.printf("Total of the Day : $ %.2f", FullTotal);

    }
}

{我的问题}

1. 当提示“按 1 进入租赁计算器或按 0 退出”时输入字母时，会出现错误提示，然后控制台要求再次输入。同样，当在提示“您想租用什么车辆？”时输入字母时控制台继续不停地打印行？我不知道如何解决这个问题？

2. 我希望我的程序允许进行多个计算输入。但是，在完整的计算输入(天数 * 税 * 汽车类型)之后，控制台发布汇总数据而不是循环？2a.提示“请输入租用天数。(示例；3):”并进行以下用户输入后。我如何让我的程序循环返回询问“按 1 进入租金计算器，否则按 0 退出”？仍然让 0 提示我的汇总数据？

Answer 1

我刚刚“重构”了你的代码，删除了一些过时的代码，并将一些其他代码放在其他位置。我还对变量使用了更清晰的命名，并遵循命名约定。

您遇到的问题是，您没有在每个catch block 中都有一个in.next();，这意味着在迭代时，变量继续使用相同的变量(无效)因此不断循环错误消息。

现在这段代码远非完美，它仍然可以轻松改进，但这应该可以帮助您入门。

package tests;

import java.util.InputMismatchException;
import java.util.Scanner;

public class Tester {

    public static void main(String []args){
        int count=0;
        int days;
        int cus;
        int carType;
        double dailyFee=0, nonTaxTotal, total,fullTotal=0;
        boolean checkRunOrQuit = false, chooseTypeVehicle = false, numberOfDAysChosen = false;
        Scanner in=new Scanner(System.in);


        while ( !checkRunOrQuit ) {
            System.out.print("Press 1 to enter Rental Calculator or else press 0 to quit\n");
            System.out.println("Please only enter 1 or 0. Also, please only enter number(s) not letter(s)");
            try {
                cus=in.nextInt();
                switch ( cus ) {
                    case 0: System.out.println("End of application");
                            System.exit(0); // This will actually end your application if the user enters 0, no need to verify later on
                    break;
                    case 1: checkRunOrQuit = true;
                    break;
                    default:
                            System.out.println("Number must be either 1 or 0");
                }
            } catch (InputMismatchException ex) {
                System.out.println("Invalid entry: ");
                in.next();
            }
        }

        while( !chooseTypeVehicle ) { // --> simplified comparison
            count++;
            System.out.print("What vehical would you like to rent?\n");
            System.out.println("Enter 1 for an economy car");
            System.out.println("Enter 2 for a sedan car");
            System.out.println("Enter 3 for an SUV");

            try {
                carType = in.nextInt();
                chooseTypeVehicle = true;
                switch ( carType ) {
                    case 1: dailyFee = 31.76;
                    break;
                    case 2: dailyFee = 40.32;
                    break;
                    case 3: dailyFee = 47.56;
                    break;
                    default:
                        System.out.print("Number must be 1-3\n");
                        System.out.println("Please enter 1 for an economy car");
                        System.out.println("Enter 2 for a sedan car");
                        System.out.println("Enter 3 for an SUV");
                        chooseTypeVehicle = false;
                        break;
                }
            } catch (InputMismatchException ex) {
                System.out.println("Answer must be a number");
                in.next(); // -> you forgot this one.
            }
        }

        while ( !numberOfDAysChosen ) {
            try {
                System.out.print("Please enter the number of days rented. (Example; 3) : ");
                days = in.nextInt();
                if (days <= 0) {
                    System.out.println("Number of days must be more than zero");
                } else {
                    nonTaxTotal = (dailyFee * days);
                    total = (nonTaxTotal * 1.06);
                    fullTotal+=total;
                    numberOfDAysChosen = true;
                }
            } catch(InputMismatchException ex) {
                System.out.println("Answer must be a number");
                in.next();
            }
        }
        in.close();
        System.out.println("Count of customers : " + count);
        System.out.printf("total of the Day : $ %.2f", fullTotal);
    }
}