如果陈述

Question

import java.util.Scanner;

public class EmpTest {

    public static Scanner input = new Scanner(System.in);

    public static void main(String[] args) {

// there is a second class with my constructors and other stuff of that nature        

        Employee e1 = new Employee(); 
        Employee e2 = new Employee();
        Employee e3 = new Employee();
        String no = "no";
        String yes = "yes";
        while (true) {

            System.out.println("Please enter in the employee name");
            e1.name = input.nextLine();
            System.out.println("Please enter in the salary of that employee");
            e1.salary = input.nextDouble();
            while (true) {
                System.out.println("Would you like to add a second employee?");

                String userInput = input.next();
                if (userInput.equalsIgnoreCase(yes)) {
                    System.out.println("Please enter in the employee name");
                    e2.name = input.next();
                    System.out.println("Please enter in the salary of that employee");
                    e2.salary = input.nextDouble();
                }
 //this is where my break wont terminate the loop
//the console output just asks for the second employee salary and name without waiting for a user input

                if(userInput.equalsIgnoreCase(no)) {
                    System.out.println("Okay");
                    break;
                }

                System.out.println("Would you like to add a third employee?");

                userInput = input.next();
                if (userInput.equalsIgnoreCase(yes)) {
                    System.out.println("Please enter in the employee name");
                    e3.name = input.next();
                    System.out.println("Please enter in the salary of that employee");
                    e3.salary = input.nextDouble();
                } 
                if(userInput.equalsIgnoreCase(no)) {
                    System.out.println("Okay");
                    break;
                }

            }

        }

    }
}

Answer 1

在我的第一个错误答案之后，这是正确的。正如JLS：

  

没有标签的break语句尝试将控制转移到最里面   封闭开关，同时，做，或立即封闭的声明   方法

所以在你的情况下，你是break内部while(true) - 循环。

如果您想要break某些“外部”区块，则必须使用break这样的标签：

loop:
  while(true) {
     .....
     while(true) {
        ...
        break loop;
     }
  }

Answer 2

你的break语句在while循环中打破内部但是没有break语句用于外部while循环。

Answer 3

你必须提供2个break语句，一个用于内部while循环，另一个用于外部while循环。

Answer 4

以下是对代码的一些解释的答案：

import java.util.Scanner;

public class EmpTest {

    public static Scanner input = new Scanner(System.in);

    public static void main(String[] args) {


        Employee e1 = new Employee(); 
        Employee e2 = new Employee();
        Employee e3 = new Employee();
        String no = "no";
        String yes = "yes";

        //initialized userInput here so that we can use it on the outer loop
        String userInput="";   

        while (true) {

            System.out.println("Please enter in the employee name");
            e1.name = input.nextLine();
            System.out.println("Please enter in the salary of that employee");
            e1.salary = input.nextDouble();
            input.nextLine();
            //nextDouble() reads only the double and doesn't finish the line, so we need to add nextLine() method after nextDouble()

            while (true) {

                System.out.println("Would you like to add a second employee?");
                userInput = input.nextLine();

                if (userInput.equalsIgnoreCase(yes)) {
                    System.out.println("Please enter in the employee name");
                    e2.name = input.nextLine();
                    System.out.println("Please enter in the salary of that employee");
                    e2.salary = input.nextDouble();

                    //again
                    input.nextLine();
                }

                if(userInput.equalsIgnoreCase(no)) {
                    System.out.println("Okay");
                    break;
                }

                System.out.println("Would you like to add a third employee?");

                userInput = input.nextLine();
                if (userInput.equalsIgnoreCase(yes)) {
                    System.out.println("Please enter in the employee name");
                    e3.name = input.nextLine();
                    System.out.println("Please enter in the salary of that employee");
                    e3.salary = input.nextDouble();
                    input.nextLine();
                } 

                if(userInput.equalsIgnoreCase(no)) {
                    System.out.println("Okay");
                    break;
                }

            }
            //do the remaining things 
            //add the condition for breaking the outer loop if there's any
            break;
        }
        //never forget to close the scanner
        input.close();
    }
}

  

一些注意事项：

     

  

1. nextDouble（）读取只有1次而未完成该行，所以我   添加了input.nextLine（）来完成该行。

  

2. 我刚在内循环后面的外循环上添加了一个中断。       我不知道你是否有打破外环的条件，或者       如果在打破内心之后你想做什么的话       环

  

3. 您也可以将该循环转换为方法，只需使用“return”       声明要突破这个方法。我不知道是否允许       但是，我只是坚持你如何创建程序并进行修改       它有点。

  

4. 使用后永远不要忘记关闭扫描仪