函数陷入循环

Question

对于一项学校作业，我的任务是将每项工作分成一个单独的功能。我在使用 doAgain() 时遇到问题的函数是我会选择包含在 main() 中的东西。

我很难让这个功能按我的需要工作。目标是获取用户输入，对其执行操作，然后提示用户查看他们是否想再次运行该作业。

当函数 doAgain() 触发时，如果输入“0”，它会终止程序，但如果输入“1”，它将无法重新运行主程序逻辑。

我确定我遗漏了一些简单的东西，但我一直在敲我的头。大家有没有机会提供一些提示？

这是我的代码：

import java.util.Scanner;

public class numbersAssignment {

    static int numberOne = 0;
    static int numberTwo = 0;
    static int numberThree = 0;
    static int largest = 0;
    static int smallest = 0;
    static int product1 = 0;
    static int sum = 0;
    static int average = 0;
    static boolean numbersDiffer = false;
    static int doItAgain = 1;

    public static void main(String[] args) {

        while (doItAgain != 0) {
            while (numbersDiffer != true) {
                numberOne = getNumber();
                numberTwo = getNumber();
                numberThree = getNumber();
                if (verifyDiff(numberOne, numberTwo, numberThree)) {
                    calcPrintNumbers(numberOne, numberTwo, numberThree);
                    numbersDiffer = true;
                }
            }
            //where it all goes wrong - doAgain() stuck...
            doItAgain = (doAgain());
        } 
    }//main

     /*
     ******************************************************************************
     * getNumber:                                                                 *
     *    This method will ask the user for the number that is to be used in the  *
     *    program. All numbers MUST BE INTEGERS, and must use DIFFERENT values.   *                                   *
     ******************************************************************************/     
     public static int getNumber() {
                int number = 0;   

                Scanner input = new Scanner(System.in);
                boolean done = false;
                while (done != true) {
                    try {
                        System.out.println("Please enter a UNIQUE integer for the program ===>   ");
                        number = input.nextInt();
                        if (number <= 0){
                            throw new NumberFormatException();
                        }
                        done = true;
                    }//try
                    catch (Exception message) {
                        input.nextLine();
                        System.out.println("Bad input, retry");
                    }//catch

                }//while
                return number;

         }//getNumber

     /*
     ******************************************************************************
     * calcPrintNumbers:                                                          *
     *     This method will recieve the three user input variables. The program   *
     *     will then calculate and print, the SUM,AVERAGE,PRODUCT,LARGEST, as well*
     *     as the SMALLEST of the three numbers. It will then print the results,  *
     *     AS WELL AS THE VALUES STORED IN THE THREE VARIABLES.                   *        
     ******************************************************************************/           
    public static void calcPrintNumbers(int numberOne, int numberTwo, int numberThree)
         {
              System.out.println("The smallest number is: " + Math.min(numberOne, Math.min(numberTwo, numberThree)));
              System.out.println("The largest number is: " + Math.max(numberOne, Math.max(numberTwo, numberThree)));
              System.out.println("The average is: " + ((numberOne + numberTwo + numberThree) /3));
              System.out.println("The product is: " + Math.multiplyExact(numberOne, Math.multiplyExact(numberTwo, numberThree)) );
              System.out.println("The sum is: " + (numberOne + numberTwo + numberThree));

         }//End of the calcSumPrint method         

     /*
     *******************************************************************************
     * doAgain:                                                                  *
     *    This method will NOT receive incoming data, but it will it will          *
     *    ask for, verify, and return the users choice of whether to continue the  *
     *    program or not. The code looks for a choice of 1 to end the program,     *
     *    ANY OTHER INTEGER will continue to run the program.                      *
      ******************************************************************************/
     public static int doAgain()
         {
               int usersChoice = 0;
               System.out.println("Enter '0' to quit, or '1' to run again: ");
               Scanner input = new Scanner(System.in);     
               usersChoice = input.nextInt();
               return usersChoice;  
         }//End of the getChoice method         

     /*
     *******************************************************************************
     * verifyDiff:                                                                 *
     *    This method accepts the three variable as arguments. It then compares all*                     *
     *    three to see if any values are the same. If they ARE, the method returns *
     *    a false, if all three variable are NOT the same, the method returns true.*
     *******************************************************************************/ 
     public static boolean verifyDiff(int numberOne, int numberTwo, int numberThree)
         {
          boolean allDiff = false;            
           if(numberOne != numberTwo && numberOne != numberThree && numberTwo != numberThree)
               allDiff = true;      
           else {
               System.out.println("You tried to use a duplicate number, try again: ");
           }
          return allDiff;
         }//End of the getChoice method        
}

非常感谢！

Answer 1

当用户要求再次执行时，您需要将numbersDiffer的值重新设置为false，否则将跳过内部while循环并通过调用doAgain 方法（永远...）。

像这样：

  while (doItAgain != 0) {
        numbersDiffer = false;
        while (numbersDiffer != true) {
        [...]

或者因为doItAgain变量是静态的，直接在doAgain方法中。顺便说一下，boolean 类型会更合适。

演示：http://ideone.com/HGGbkU

Answer 2

您需要将 numbersDiffer 的值重置为 false

在请求输入之后或在内部循环之外添加此行 numbersDiffer = false。

像这样

doItAgain = (doAgain());
numbersDiffer = false;

你的程序没有执行你的主要逻辑是因为你没有重新设置numbersDiffer的值，它一直是true，所以你需要重新设置为false为了满足条件

函数陷入循环

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java.util.scanner