在java中以字符串格式将所有值相乘在一起

Question

我只有几个小时练习和学习Java，所以我仍然在学习基础知识。

我从一个文本文件，其中包含读取值：

单 112.50

主 2227.50

阁楼 5000.00

（所以它显示为运行时） 房间类型：单人，预订：6 0，房间价格：£112.00，收入：£6,750.00，税：1350.00 所以第四个房间。

我已经打印了需要的字符串格式的所有值。不过，我的问题很简单。

我只是想将所有收入加在总收入变量中，并将所有paidTax一起添加到totalpaidTax变量中，然后继续打印出来，基本显示所有房间的总税收和总收入。 虽然，我只是不知道如何写它。我尝试过多次尝试，但没有运气。 这是我目前的代码。

import java.io.FileReader; 
import java.util.Scanner; 
public class WagesCalculator { 
public static void main(String[] args) throws Exception { 
    Scanner input = new Scanner(System.in); 
    Scanner file = new Scanner(new FileReader("task3.txt")); 
    Scanner sc = new Scanner(System.in); 

    //Current tax variable value 
    double tax = 20; 

    //User Input Y or N to change tax variable value 
    System.out.println("- - Hotel Tax System - -"); 
    System.out.print("Do you want to specify a custom Tax Rate? [Y|N]: "); 

    //if statement to change tax variable value subject to Y or N 
    if (sc.next().equalsIgnoreCase("Y")) { 
     System.out.print("Please enter the new tax value: "); 
     tax = new Scanner(System.in).nextInt(); 
     } 

    //Prints out current tax value 
    System.out.println("The current tax rate is " + tax+"."); 

    while (file.hasNext()) { 
     String name = file.next(); 
     int numberOfBookings = file.nextInt(); 
     double price = file.nextDouble(); 
     double income = numberOfBookings * price; 
     double paidTax = income*(tax/100); 
     //String format print out final calculations 
     System.out.printf("Room Type: %s, Bookings: %d, Room Price: £%.2f, Income: £%.2f, Tax: %.2f %n", name, numberOfBookings, price, income, paidTax); 

     } 
    file.close(); 
    } 

}

Answer 1

对象是你的朋友。

• 在输入中为每个房间创建一个对象。
• 将房间存储在列表中。
• 来自列表的聚合值。

• 相应打印。

  import java.io.FileNotFoundException; 
  import java.io.FileReader; 
  import java.util.ArrayList; 
  import java.util.List; 
  import java.util.Scanner; 
  
  public class WagesCalculator 
  { 
  
      public static void main(String[] args) 
      throws Exception 
      { 
      WagesCalculator wc = new WagesCalculator(); 
      wc.calculate(); 
      } 
  
      public void calculate() 
      throws FileNotFoundException 
      { 
      Scanner file = new Scanner(new FileReader("task3.txt")); 
      Scanner sc = new Scanner(System.in); 
  
      // Current tax variable value 
      double tax = 20; 
  
      // User Input Y or N to change tax variable value 
      System.out.println("- - Hotel Tax System - -"); 
      System.out.print("Do you want to specify a custom Tax Rate? [Y|N]: "); 
  
      // if statement to change tax variable value subject to Y or N 
      if (sc.next().equalsIgnoreCase("Y")) 
      { 
       System.out.print("Please enter the new tax value: "); 
       tax = new Scanner(System.in).nextInt(); 
      } 
  
      // Prints out current tax value 
      System.out.println("The current tax rate is " + tax + "."); 
  
      List<Room> rooms = new ArrayList<Room>(); 
  
      while (file.hasNext()) 
      { 
       String name = file.next(); 
       int numberOfBookings = file.nextInt(); 
       double price = file.nextDouble(); 
       rooms.add(new Room(tax, name, numberOfBookings, price)); 
      } 
  
      file.close(); 
  
      rooms.stream().forEach(e -> System.out.println(e)); 
      double totalIncome = rooms.stream().map(r -> r.income) 
      .reduce((a, b) -> a + b).orElse(0.0); 
      double totalTax = rooms.stream().map(r -> r.tax).reduce((a, b) -> a + b) 
      .orElse(0.0); 
      System.out.printf("Total income was: %d\nTotal tax was %d\n", totalIncome, 
      totalTax); 
      } 
  
      class Room 
      { 
      double tax; 
  
      String name; 
  
      int numberOfBookings; 
  
      double price; 
  
      double income; 
  
      double paidTax; 
  
      public Room(double tax, String name, int numberOfBookings, double price) 
      { 
       this.tax = tax; 
       this.name = name; 
       this.numberOfBookings = numberOfBookings; 
       this.price = price; 
       this.income = numberOfBookings * price; 
       this.paidTax = income * (tax/100); 
      } 
  
      @Override 
      public String toString() 
      { 
       return String.format(
       "Room Type: %s, Bookings: %d, Room Price: £%.2f, Income: £%.2f,   Tax: %.2f %n", 
        name, numberOfBookings, price, income, paidTax); 
      } 
      } 
  }