無法獲取while循環工作

Question

我正在使用while循環使其在用戶輸入除「Yes」或「No」之外的任何內容時，它會告訴他們輸入新的內容，但每次輸入其他內容時只是垃圾郵件「這不是一個選項」，而不是從頂端開始。有人可以向我解釋爲什麼？先謝謝你。

   using System; 

class CalculatorProgram 
{ 
    //varibale for do-while loop 
    private static string endAnswer; 
    public static void Main() // <----- The Entry point 
    { 
    //Variables 
    string Choice1; 
    string mathChoice; 
    decimal Num1; 
    decimal Num2; 
    decimal Answer; 
    bool userWrong = true; 

    Console.Write("Would you like to use Lane's Custom Calculator?(Yes/No): "); 
    Choice1 = Console.ReadLine(); 

    while(userWrong) 
    { 
     if (Choice1 == "Yes") 

     { 
      do 
      { 
       Console.Write("Would you like to Add, Subtract, Multiply, or Divide? (Case Sensitive): "); 
       mathChoice = Console.ReadLine(); 

       //User inputs the 2 numbers 


       //Math Choices 
       if (mathChoice == "Add") 
       { 
        Console.WriteLine("What 2 numbers would you like to use?"); 
        Console.Write("Number 1 is: "); 
        Num1 = decimal.Parse(Console.ReadLine()); 

        Console.Write("Number 2 is: "); 
        Num2 = decimal.Parse(Console.ReadLine()); 

        Answer = Num1 + Num2; 
        Console.WriteLine("Your expression is: " + Num1 + " + " + Num2 + " = " + Answer); 
       } 

       else if (mathChoice == "Subtract") 
       { 
        Console.WriteLine("What 2 numbers would you like to use?"); 
        Console.Write("Number 1 is: "); 
        Num1 = decimal.Parse(Console.ReadLine()); 

        Console.Write("Number 2 is: "); 
        Num2 = decimal.Parse(Console.ReadLine()); 
        Answer = Num1 - Num2; 
        Console.WriteLine("Your expression is: " + Num1 + " - " + Num2 + " = " + Answer); 
       } 

       else if (mathChoice == "Multiply") 
       { 
        Console.WriteLine("What 2 numbers would you like to use?"); 
        Console.Write("Number 1 is: "); 
        Num1 = decimal.Parse(Console.ReadLine()); 

        Console.Write("Number 2 is: "); 
        Num2 = decimal.Parse(Console.ReadLine()); 
        Answer = Num1 * Num2; 
        Console.WriteLine("Your expression is: " + Num1 + " X " + Num2 + " = " + Answer); 
       } 

       else if (mathChoice == "Divide") 
       { 
        Console.WriteLine("What 2 numbers would you like to use?"); 
        Console.Write("Number 1 is: "); 
        Num1 = decimal.Parse(Console.ReadLine()); 

        Console.Write("Number 2 is: "); 
        Num2 = decimal.Parse(Console.ReadLine()); 
        Answer = Num1/Num2; 
        Console.WriteLine("Your expression is: " + Num1 + "/" + Num2 + " = " + Answer); 
       } 

       else 
       { 
        Console.WriteLine("This is not an option! Shutting Down.."); 
        Console.ReadKey(); 
        Environment.Exit(0); 
       } 


       //varibale for while loop to continue if selected Yes. 
       Console.Write("Another Equation?: "); 
       endAnswer = Console.ReadLine(); 



      } while (endAnswer == "Yes"); 


      //Goodbye Message 
      Console.WriteLine("Thank you for using my program, goodbye "); 
      Console.ReadKey(); 
      Environment.Exit(0); 
      userWrong = false; 
     } 
     //If someone selects no for wanting to use my program. 
     else if (Choice1 == "No") 
     { 
      Console.WriteLine("Thank you for using my program, goodbye "); 
      Console.ReadKey(); 
      Environment.Exit(0); 
     } 
     else 
     { 
      Console.WriteLine("That is not an option"); 
      Console.ReadLine(); 


     } 

    } 





    } 
} 

Answer 1

該程序正在等待用戶輸入新的答案後，它打印出「這不是一個選項」，你只是從來沒有提示他們。你也絕不會存儲Choice1再根據他們對新的輸入，所以它總是會檢查您do-while循環的第一if條件用他們最初插嘴說。

要解決它，你else分支體更改爲類似這個。

//... 
else 
{ 
    Console.WriteLine("That is not an option"); 
    // reprompt the user so they know to type something in 
    Console.Write("Would you like to use Lane's Custom Calculator?(Yes/No): "); 
    // store the new choice to recheck next loop iteration 
    Choice1 = Console.ReadLine(); 
} 

Answer 2

可能你的問題是你沒有對輸入做出正確的驗證。 現在，您從控制檯讀取輸入並與靜態字符串進行比較，因此 「添加」與「添加」不同，並且與「添加（空間）」不同。 我建議你做一個更強大的輸入驗證：

Console.Write("Would you like to Add, Subtract, Multiply, or Divide? (Case Sensitive): "); 
mathChoice = Console.ReadLine(); 
mathChoice = mathChoice.ToUpper().Trim(); 
//User inputs the 2 numbers 

//Math Choices 
if (mathChoice == "ADD") 
{ 
    Console.WriteLine("What 2 numbers would you like to use?"); 
    .... 
}