如何在输入特定字符串后停止java中的while循环？

Question

在控制台中输入"End“后，我试图停止一个接受整数的循环，但我似乎找不到一种方法来这样做。

Scanner scan = new Scanner(System.in);
        int bottles = Integer.parseInt(scan.nextLine()) * 750;
        int cnt = 1;
        int platesTotal;
        int potsTotal;
        int nrPlates = 0;
        int nrPots = 0;
        while(true){
            int plates = scan.nextInt();
            platesTotal = plates * 5;
            if(cnt%3==0) {
                int pots = scan.nextInt();
                nrPots = nrPots + pots;
                nrPlates = nrPlates + pots;
                potsTotal = pots * 15;

                if (bottles < potsTotal + platesTotal) {
                    System.out.println("Not enough detergent, " + (potsTotal + platesTotal - bottles) + " ml. more necessary!");
                    break;
                }
                else
                    if(bottles >= potsTotal + platesTotal) {
                        String enough = scan.nextLine();
                        if (enough.equals("End")) {
                            if (bottles >= potsTotal + platesTotal) {
                                System.out.println("Detergent was enough!");
                                System.out.println(nrPlates + " dishes and " + nrPots + "pots were washed.");
                                System.out.printf("Leftover detergent %d ml.", bottles - potsTotal - platesTotal);
                                break;
                            }
                        }
                    }
            }
            cnt++;
        }

输入字符串("End")后，它需要向我显示碟子和罐子的总数，以及它还剩下多少洗涤剂，如果所需的洗涤剂数量超过可用数量，它需要显示还需要多少洗涤剂。

Answer 1

尝试使用此String enough = scan.next();而不是scan.nextLine();

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Answer 2

我建议将消息打印到控制台，以便向用户确认您想要的输入。否则，它只会显示一个空白窗口。我还建议您定义一个布尔变量来转义while循环，同时将足够的值切换为.next而不是.nextLine。这样，您可以将布尔值重新定义为false，以中断while循环，同时还可以获得所需的输出，以便更好地控制程序输出。这是用所有条目1编译的：

package com.climatedev.test;

import java.util.Scanner;

public class Test {


    public static void main(String[] args) {
        System.out.println("How many bottles?");
        Scanner scan = new Scanner(System.in);
        int bottles = scan.nextInt() * 750;
        int cnt = 1;
        int platesTotal;
        int potsTotal;
        int nrPlates = 0;
        int nrPots = 0;
        boolean run = true;
        while(run){
             System.out.println("How many plates?");
             int plates = scan.nextInt();
             platesTotal = plates * 5;
             if(cnt%3==0) {
                 int pots = scan.nextInt();
                  nrPots = nrPots + pots;
                  nrPlates = nrPlates + pots;
                  potsTotal = pots * 15;

              if (bottles < potsTotal + platesTotal) {
                   System.out.println("Not enough detergent, " + (potsTotal + platesTotal - bottles) + " ml. more necessary!");
                   break;
               }
              else
                  if(bottles >= potsTotal + platesTotal) {
                      System.out.println("Would you like to end the program? (Enter End)");
                      String enough = scan.next();
                  if (enough.equals("End")) {
                      if (bottles >= potsTotal + platesTotal) {
                          System.out.println("Detergent was enough!");
                          System.out.println(nrPlates + " dishes and " + nrPots + "pots were washed.");
                          System.out.printf("Leftover detergent %d ml.", bottles - potsTotal - platesTotal);
                          run = false;
                          System.out.println("Goodbye");
                          break;
                        }
                    }
                }
            }
        cnt++;
         }
    }
}

我还稍微更改了你的瓶子，使用nextInt，但这取决于你的使用。如果您认为最终用户可能会键入类似“瓶子的数量是...”之类的内容这样会更好，但是为什么不使用更简单的nextInt调用呢？

Answer 3

如果要将scanner对象同时用于字符串和数字，则必须解析数字：

 Scanner scanner = new Scanner(System.in);
 String str = scanner.nextLine();
 int num = Integer.parseInt(scanner.nextLine());

或者您可以有两个扫描器(一个用于字符串，另一个用于数字)：

 Scanner strScanner = new Scanner(System.in);
 Scanner numScanner = new Scanner(System.in);
 String str = strScanner.nextLine();
 int num  = numScanner.nextInt();