JAVA每次循环返回时如何将变量值更改为零

Question

我使用 for 循环要求用户输入要购买的商品并计算价格...然后它会询问用户是否会继续添加另一个商品...所以它又是一个循环...然后当用户停止购买...然后它会计算总价...所以我使用：

    totalprice+=total;

但是当外部 for 循环将为第二个客户重复时...totalprice 的价值仍然是第一个客户的购买价值，所以它会加起来...无论如何我可以每次都将 totalprice 值恢复为 0它为第二个客户循环？

这是我的那个方法的代码

public static void makeOrder() {
    for (index = 0; index < date.length; index++) {
        double price = 0;
        int order;
        char addOrder;
        String resume;
        System.out.print("\nCustomer" + (index + 1));
        System.out.print("\nEnter your name: ");
        String name = input.nextLine();
        System.out.print("Enter the date of reservation(DD/MM/YY): ");
        date[index] = input.nextLine();
        System.out.print("Enter your type of table(Couple/Family): ");
        String table = input.nextLine();
        do {
            System.out.println("BERKAT RESTAURANT MENU:\n\n MEALS \n1-Beef      Bolognese: RM17.00\n2-Chicken Marsala: RM 13.00\n3-Spaghetti Carbonara: RM  9.00\n4-Fillet Mignon: RM12.00");
            System.out.println("\nDRINKS \n5-Strawberry Fruit Punch: RM6.00 \n6-Vanilla Smoothies: RM 7.00\n7-Sky Juice: RM 3.00");
            System.out.print("\nEnter your choice of meals/drink: ");
            order = input.nextInt();
            System.out.print("Enter the quantity: ");
            int quantity = input.nextInt();
            System.out.print("Do you want to add order?(Y/N): ");
            addOrder = input.next().charAt(0);

            double total = calculatePrice(order, quantity);

            subtotal += total;

        } while (addOrder != 'N');

        System.out.println("");

        System.out.println("$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$");
        System.out.printf("The total price you have to pay is: RM%6.2f ", subtotal);
        System.out.println("");
        System.out.println("Thank you for coming to our restaurant, Please come again!");
        System.out.println("$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$");

    }
}// makeOrder method

每次“for”循环返回时，我都想将小计值恢复为 0.00

Answer 1

您要确保在外部 for 循环开始时将 subtotal 初始化为 0。这样对于每个客户，它始终为 0，无论添加到订单中的商品数量如何。

public static void makeOrder() {
  double subtotal = 0;
  for(index = 0, index < date.length; index++) {
    subtotal = 0;
    /* your other code here */
  }
}

Answer 2

您应该在 for 循环开始时将 subtotal 初始化为 0。

public static void makeOrder()
{
  for(index=0;index<date.length;index++)
  {
    double subtotal=0;
    double price=0;
    int order;
    char addOrder;
    String resume;
    System.out.print("\nCustomer"+(index+1));
    System.out.print("\nEnter your name: ");
    String name=input.nextLine();
    System.out.print("Enter the date of reservation(DD/MM/YY): ");
    date[index]=input.nextLine();
    System.out.print("Enter your type of table(Couple/Family): ");
    String table=input.nextLine();
    do{
      System.out.println("BERKAT RESTAURANT MENU:\n\n MEALS \n1-Beef      Bolognese: RM17.00\n2-Chicken Marsala: RM 13.00\n3-Spaghetti Carbonara: RM  9.00\n4-Fillet Mignon: RM12.00");
      System.out.println("\nDRINKS \n5-Strawberry Fruit Punch: RM6.00 \n6-Vanilla Smoothies: RM 7.00\n7-Sky Juice: RM 3.00");
      System.out.print("\nEnter your choice of meals/drink: ");
      order=input.nextInt();
      System.out.print("Enter the quantity: ");
      int quantity=input.nextInt();
      System.out.print("Do you want to add order?(Y/N): ");
      addOrder=input.next().charAt(0);

      double total=calculatePrice(order,quantity);

      subtotal+=total;

    }while(addOrder!='N');

    System.out.println("");
    System.out.println("$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$");
    System.out.printf("The total price you have to pay is: RM%6.2f ",subtotal);
    System.out.println("");
    System.out.println("Thank you for coming to our restaurant, Please come again!");
    System.out.println("$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$");

  }
}//makeOrder method

Answer 3

谢谢你们的帮助...所以我声明 subtotal=0.00 它就像一个魅力

   public static void makeOrder()
  {
  for(index=0;index<date.length;index++)
  {
  double price=0;
  double subtotal=0.00;
  int order;
  char addOrder;
  String resume;
     System.out.print("\nCustomer"+(index+1));
     System.out.print("\nEnter your name: ");
     String name=input.nextLine();
     System.out.print("Enter the date of reservation(DD/MM/YY): ");
     date[index]=input.nextLine();
     System.out.print("Enter your type of table(Couple/Family): ");
     String table=input.nextLine();
     do{
     System.out.println("BERKAT RESTAURANT MENU:\n\n MEALS \n1-Beef Bolognese: RM17.00\n2-Chicken Marsala: RM 13.00\n3-Spaghetti Carbonara: RM 9.00\n4-Fillet Mignon: RM12.00");
     System.out.println("\nDRINKS \n5-Strawberry Fruit Punch: RM6.00 \n6-Vanilla Smoothies: RM 7.00\n7-Sky Juice: RM 3.00");
     System.out.print("\nEnter your choice of meals/drink: ");
     order=input.nextInt();
     System.out.print("Enter the quantity: ");
     int quantity=input.nextInt();
     System.out.print("Do you want to add order?(Y/N): ");
     addOrder=input.next().charAt(0);

     double total=calculatePrice(order,quantity);

     subtotal+=total;

     }while(addOrder!='N');

     System.out.println("");

  System.out.println("$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$");
  System.out.printf("The total price you have to pay is: RM%6.2f ",subtotal);
  System.out.println("");
  System.out.println("Thank you for coming to our restaurant, Please come again!");
  System.out.println("$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$");


     }
     }//makeOrder method