java - 如何让它中断“当我为产品输入 -1 但不为两个 2 输入 -1 时

Question

我的结果希望我:当我在(输入产品编号)中输入-1时，它会直接中断并计算总数，但现在我必须在(输入产品编号)中输入-1并(输入产品编号)数量)只有它会破裂

import java.util.Scanner;
public class Structuredcontrols {
   public static void main(String[]args) {      
      Scanner input = new Scanner(System.in);
      double sum=0;         
      double sum2=0;        
      double sum3=0;        
      int number = 0;       
      int quantity;         

      while (number != -1) {
          System.out.print("Enter product number: ");       
          number = input.nextInt(); 

          System.out.print("Enter quantity number: ");      
          quantity = input.nextInt();
          switch (number) {    
             case 1:
                 sum += 2.98 * quantity;
                 break;
             case 2:
                 sum2 += 4.50 * quantity;
                 break;
             case 3:
                 sum3 += 9.98 * quantity;
                 break;
          }

      }
      System.out.println("Total value of product 1 is: "+sum);
      System.out.println("Total value of product 2 is: "+sum2);
      System.out.println("Total value of product 3 is: "+sum3);

   }

}

Answer 1

只需添加一个 if 语句

if(number == -1) { 
   break;
}

这是完整的代码

import java.util.Scanner;

public class structuredcontrols {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        double sum = 0;
        double sum2 = 0;
        double sum3 = 0;
        int number = 0;
        int quantity;

        while (number != -1) {

            System.out.print("Enter product number: ");
            number = input.nextInt();

            if (number == -1)
                break;
            System.out.print("Enter quantity number: ");
            quantity = input.nextInt();

            switch (number)

            {
            case 1:
                sum += 2.98 * quantity;
                break;
            case 2:
                sum2 += 4.50 * quantity;
                break;
            case 3:
                sum3 += 9.98 * quantity;
                break;
            }
        }
        System.out.println("Total value of product 1 is: " + sum);
        System.out.println("Total value of product 2 is: " + sum2);
        System.out.println("Total value of product 3 is: " + sum3);
    }

}