爲什麼這個do/while循環卡在inf中。循環？

public class Tester 
{ 
    // instance variables - replace the example below with your own 
    Scanner operation = new Scanner(System.in); 
    IntegerCalc calc = new IntegerCalc(); 



    public Tester() 
    { 

     char choice; 
     String value; 
     char again; 
    } 

    public void test() 
    { 
    char again = operation.next().charAt(0); 
     do{ 
     System.out.println("Please pick one of the following operations: 1. Addition 2. Subtraction" + 
      "3. Multiplication 4.Division 5. Modulo 6. Square 7.Square Root"); 

      int num = operation.nextInt(); 
     int ch; 
     ch = operation.nextInt(); 


      String choice; 
     choice = operation.next(); 


      switch (ch){ 
       case 1: calc.addition(num,num); 
       break; 
       case 2: calc.subtraction(num, num); 
       break; 
       case 3: calc.multiplication(num, num); 
       break; 
       case 4: calc.division(num, num); 
       break; 
       case 5: calc.modulo(num, num); 
       break; 
       case 6:calc.square(num); 
       break; 
       case 7: calc.squareRoot(num); 
       break; 
       default: System.out.println("Please enter a valid choice number."); 
      } 
       System.out.println("Type x to exit"); 



     }while(again != 'x' && again != 'X'); 
     { 

     System.out.println("Thank you for using my program!"); 




    }

//這段代碼的問題在於，它甚至不提示用戶輸入任何數據，它似乎只是被卡在一個循環中，什麼都不做。任何人都知道我能做些什麼來實現這個目標？爲什麼這個do/while循環卡在inf中。循環？

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2013-11-10 user2975182

這是否甚至編譯？靠近底部的一個括號會面對錯誤的方向。 – Tyson

您有：char again = operation.next().charAt(0);外do/while循環的，所以如果again不斷滿足while條件，你會得到一個無限循環。

來源

2013-11-10 00:35:07

你需要這個說法

System.out.println("Type x to exit");

來源

2013-11-10 00:35:45 hrv

System.out.println("Type x to exit"); 
char again = operation.next().charAt(0);

後接受來自用戶

again = operation.next().charAt(0);

字符這應該工作

來源

2013-11-10 00:36:01

爲什麼這個do/while循環卡在inf中。循環？

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