Java编程比萨饼订购系统：假设未被初始化的变量

Question

我有一个项目要求我制作披萨订购系统，除了一两个部分外，一切正常。

第一个错误的是，在第二种情况下，我有这个部分，我需要询问他们是否想要订购更多的比萨饼，如果他们输入y或Y，那么它需要循环回来询问他们的大小我想，但如果他们输入n或N，它会回到主要的菜单。是和否都将它们带回主菜单？

另一个被打破的部分是它说我没有初始化currentTotal，我不能真正启动，因为我不知道有多少人会输入。

唯一可能不起作用的是第四种情况，因为它需要消除所有内容并且jus启动程序？我刚刚做到这一点，以便toalExpence等于0，但我认为这是错误的。

它将于今晚11:59东部时间到期，但即使它没有完全解决它，我也可以使用任何帮助。 谢谢！

这个问题不只是询问如何比较字符串，事实上我甚至没有问过，所以它不是重复的。

  import java.util.Scanner;
  public class orderPizza{
  public static void main(String[] args){

    Scanner kb = new Scanner(System.in);

     double LARGE_PIZZA_PRICE = 16.99;
     double MEDIUM_PIZZA_PRICE = 14.99;
     double SMALL_PIZZA_PRICE = 12.99;
     double totalExpense = 0.00;
     double temp;
     double currentTotal = temp;

     System.out.println("Welcome to the Pizza Ordering System.");

     System.out.println("1.List prices");
     System.out.println("2.Place order"); 
     System.out.println("3.Display total amount to pay"); 
     System.out.println("4.Cancel the current order");
     System.out.println("5.Exit program");


boolean quit = false;
        do {
              System.out.println(" Please input the number of your choice to continue:");
              int choice = kb.nextInt();
              switch (choice) {
              case 1:
                    System.out.println("You've chosen List prices");
                    System.out.println("Large pizza: $"+LARGE_PIZZA_PRICE); 
                    System.out.println("Medium pizza: $"+MEDIUM_PIZZA_PRICE);
                    System.out.println("Small pizza: $"+SMALL_PIZZA_PRICE);
                    break;

              case 2:
                    System.out.println("You've chosen Place order");
                    System.out.println("Please choose the size of pizza (1. Large; 2. Medium; 3. Small;)");
                    int size = kb.nextInt();
                    System.out.println("Please input the number of pizzas you would like to order (1 - 10)");
                    int orderAmount = kb.nextInt();
                    //calculating prices
                    double subtotal = size * orderAmount;
                     if(size == 1){
                          subtotal = LARGE_PIZZA_PRICE * orderAmount;
                          temp = totalExpense + subtotal;
                          }
                     else if(size == 2){
                          subtotal = MEDIUM_PIZZA_PRICE * orderAmount;
                          temp = totalExpense + subtotal;
                          }
                     else if(size == 3){
                          subtotal = SMALL_PIZZA_PRICE * orderAmount;
                          temp = totalExpense + subtotal;
                          }
                     else if (size > 3){
                          System.out.println("Invalide number");
                          } 
                     System.out.println("Do you want to order more? (y/n)");
                       kb.nextLine();
                       String yesNo = kb.nextLine();
                       if(yesNo == "y" || yesNo == "Y"){
                          continue;
                          }
                       else if(yesNo == "n" || yesNo == "N"){
                          break;
                          }

                     break;       

              case 3:
                    System.out.println("You've chosen Display total amount to pay");
                    System.out.println("Your current total is: ");
                    break;
              case 4:
                    System.out.println("You've chosen Cancle the current order");
                    totalExpense = 0;
                    System.out.println("Your order is canceled and your total expense is 0 now.");
                    break;
              case 5:
                    quit = true;
                    break;
              default:
                    System.out.println("Invalid choice.");
              }
        } while (!quit);
        System.out.println("Bye-bye!");
  }

}