if文が毎回私のカウンタをJavaで上書きします

Question

私は列車の切符の費用を計算するプログラムを作成しようとしています。私は現在、現在のコストに任意の値引きを加える方法を行っています。私はif文を使用していますが、以前の計算を上書きするたびに使用しています。これをどうやって止めるのですか？

ここに私の方法です...現在の現在のコストと量は、ユーザーが望むチケットの量です。

public static double calcDiscounts(double a, double[] b) { 

    double counter = 0; 
    double current = b[1]; 
    double amount = b[0]; 

     System.out.println("You may be valid for discounts. Please answer these questions :" 
       + "\nDo you have any under 10's travelling with you?\nType 1 for Yes\nType 2 for no"); 
     if (input.nextInt() == 1) { 
      System.out.println("How many under 10's will be travelling with you?"); 
      int under = input.nextInt(); 
      if (under > amount - 1) { 
       System.out.println("Invalid input - there must be at least one adult travelling alongside."); 
      } 
      double temp = a * under; 
      counter += current - temp; 


      System.out.println("The cost of your ticket(s) is now " + counter); 
     } 
     else { 
      counter = current; 
     } 

     System.out.println("Is anybody travelling with you under 16?\nType 1 for Yes\nType 2 for no"); 
     if (input.nextInt() == 1) { 
      System.out.println("How many under 16's will be travelling with you?"); 
      int sixteen = input.nextInt(); 
      if (sixteen > amount) { 
       System.out.println("Invalid input - you don't have this many tickets."); 
      } else { 
       double temp = a * 0.50; 
       double next = temp * sixteen; 
       counter = current - next; 
       System.out.println("The cost of your ticket(s) is now " + counter); 
      } 
     } 
     else { 
      counter = current; 
     } 

     System.out.println("Is anybody travel a student?\nType 1 for Yes\nType 2 for no"); 
     if (input.nextInt() == 1) { 
      System.out.println("How many students will be travelling?"); 
      int student = input.nextInt(); 
      if (student > amount) { 
       System.out.println("Invalid input - you don't have this many tickets."); 
      } else { 
       double temp = a * 0.25; 
       double next = temp * student; 
       counter = current - next; 

       System.out.println("The cost of your ticket(s) is now " + counter); 
      } 
     } 
     else { 
      counter = current; 
     } 

     System.out.println("Is anybody travelling over 60?\nType 1 for Yes\nType 2 for no"); 
     if (input.nextInt() == 1) { 
      System.out.println("How many over 60's will be travelling?"); 
      int sixty = input.nextInt(); 
      if (sixty > amount) { 
       System.out.println("Invalid input - you don't have this many tickets."); 
      } else { 
       double temp = a * 0.60; 
       double next = temp * sixty; 
       counter = current - next; 

       System.out.println("The cost of your ticket(s) is now " + counter); 
      } 
     } 
     else { 
      counter = current; 
     } 
    return counter; 
} 

Answer 1

あなたは、各if-else句でカウンタの値を上書きしている、ともcurrentが十分になるためcounterを使用する必要はありません。

public static double calcDiscounts(double a, double[] b) { 

    double current = b[1]; 
    double amount = b[0]; 

    Scanner input = new Scanner(System.in); 
    System.out.println("You may be valid for discounts. Please answer these questions :" 
      + "\nDo you have any under 10's travelling with you?\nType 1 for Yes\nType 2 for no"); 
    if (input.nextInt() == 1) { 
     System.out.println("How many under 10's will be travelling with you?"); 
     int under = input.nextInt(); 
     if (under > amount - 1) { 
      System.out.println("Invalid input - there must be at least one adult travelling alongside."); 
     } 
     double temp = a * under; 
     current -= temp; 

     System.out.println("The cost of your ticket(s) is now " + current); 
    } 

    System.out.println("Is anybody travelling with you under 16?\nType 1 for Yes\nType 2 for no"); 
    if (input.nextInt() == 1) { 
     System.out.println("How many under 16's will be travelling with you?"); 
     int sixteen = input.nextInt(); 
     if (sixteen > amount) { 
      System.out.println("Invalid input - you don't have this many tickets."); 
     } else { 
      double temp = a * 0.50; 
      double next = temp * sixteen; 
      current -= next; 
      System.out.println("The cost of your ticket(s) is now " + current); 
     } 
    } 

    System.out.println("Is anybody travel a student?\nType 1 for Yes\nType 2 for no"); 
    if (input.nextInt() == 1) { 
     System.out.println("How many students will be travelling?"); 
     int student = input.nextInt(); 
     if (student > amount) { 
      System.out.println("Invalid input - you don't have this many tickets."); 
     } else { 
      double temp = a * 0.25; 
      double next = temp * student; 
      current -= next; 

      System.out.println("The cost of your ticket(s) is now " + current); 
     } 
    } 

    System.out.println("Is anybody travelling over 60?\nType 1 for Yes\nType 2 for no"); 
    if (input.nextInt() == 1) { 
     System.out.println("How many over 60's will be travelling?"); 
     int sixty = input.nextInt(); 
     if (sixty > amount) { 
      System.out.println("Invalid input - you don't have this many tickets."); 
     } else { 
      double temp = a * 0.60; 
      double next = temp * sixty; 
      current -= next; 

      System.out.println("The cost of your ticket(s) is now " + current); 
     } 
    } 
    return current; 
} 

：

は、このコードを考えてみましょう