C＃控制台程序循环问题

Question

我试图创建一个C＃程序，它为用户提供了3个选项：

1. 创建名称（获取用户输入他们的名字和姓氏，并显示为J.Blogg ）

2. 若干阶乘（输出作为例如5x4x3x2x1 = 120，其为5

3. 阶乘退出

我有程序工作正常，但当我尝试选择选项1（创建名称），然后选项2它转到选项1，然后它不让我退出（选项3）。 我是新来的编程，所以它可能很简单，但我不明白我要去哪里错了， 任何帮助将是非常伟大的。 我想保持相同的布局，我认为我的问题可能是循环，但任何帮助和改进都会很好。

static void Main(string[] args) 
    { 

     //The value returned from the topmenu method is stored in a variable called useroption 
     int useroption; 
     useroption = topmenu(); 

     // excute while loop untill option is not 1-3 
     do 
     { 


      if (useroption == 1) 
      { 
       Console.Clear(); 
       Createname(); 
       //break; 
      } 

      if (useroption == 2) 
      { 
       Console.Clear(); 
       factorial(); 
       // break; 
      } 

      if (useroption == 3) 
      { 
       Console.Clear(); 
       Console.WriteLine("Thank you for using my program, Good bye !!!"); 
       // break; 
      } 

      //topmenu(); 
      } 
     while (useroption != 3); 




     Console.ReadKey(); 


    } 

    //This method present the user with an menu which the user has a choice of 3 options 
    static int topmenu() 
    { 
     int option; 
     string option_str; 

     Console.Clear(); 
     Console.WriteLine("********************************************************************************"); 
     Console.WriteLine("********************************************************************************"); 
     Console.WriteLine("*********  OPTION 1 : Enter your name        *********"); 
     Console.WriteLine("*********  OPTION 2 : Enter the number you want to factorise  *********"); 
     Console.WriteLine("*********  OPTION 3 : Quit           *********"); 
     Console.WriteLine("********************************************************************************"); 
     Console.WriteLine("********************************************************************************"); 
     option_str = Console.ReadLine(); 

     option = Convert.ToInt32(option_str); 
     Console.Clear(); 

     if (option < 0 || option > 3) 
     { 
      Console.WriteLine("You have enter an invald option,"); 
      Console.WriteLine("Please chose a option between 1-3 (Please press any key to return to main menu)"); 
      Console.ReadLine(); 
      Console.Clear(); 
      topmenu(); 
     } 
     else 
     { 
      Console.WriteLine("You have chosen option: " + option + " (Please press any key continue)"); 
     } 
     Console.ReadKey(); 
     return option; 




    } 
    //this method asks user to enter their name (1st name then surname) and presents it back to the user as their intial(1st name) and surname 
    static void Createname() 
    { 
     string firstname, surname, firstname_str, surname_str, userfullname; 

     Console.Clear(); 
     Console.WriteLine("Please enter your first name "); 
     firstname_str = Console.ReadLine(); 
     firstname = Convert.ToString(firstname_str); 
     Console.Clear(); 
     Console.WriteLine("Please enter your surname name "); 
     surname_str = Console.ReadLine(); 
     surname = Convert.ToString(surname_str); 
     Console.Clear(); 
     userfullname = firstname + surname; 

     Console.WriteLine("You have entered your name as " + firstname[0] + "." + surname); 
     Console.WriteLine("(Please press any key to return to main menu)"); 
     Console.ReadKey(); 
     topmenu(); 

    } 

    //this method asks the user to enter a number and returns the factorial of that number 
    static double factorial() 
    { 


     string number_str; 
     double factorial = 1; 



     Console.WriteLine("Please enter number"); 
     number_str = Console.ReadLine(); 

     int num = Convert.ToInt32(number_str); 


     // If statement is used so when the user inputs 0, INVALID is outputed 

     if (num <= 0) 
     { 
      Console.WriteLine("You have enter an invald option"); 
      Console.WriteLine("Please enter number"); 
      number_str = Console.ReadLine(); 
      Console.Clear(); 


      num = Convert.ToInt32(number_str); 
      //Console.Clear(); 
      //topmenu(); 
      //number_str = Console.ReadLine(); 
     } 

     if (num >= 0) 
     { 

      while (num != 0) 
      { 
       for (int i = num; i >= 1; i--) 
       { 
        factorial = factorial * i; 
        Console.Write(i + " * "); 

       } 


        Console.WriteLine("= "+factorial+ " which is factorial of " + number_str.ToString()); 
        Console.WriteLine("(please any key to return to main menu)"); 
        Console.ReadKey(); 
        Console.Clear(); 
        topmenu(); 

      } 

     } 


     return factorial; 




    } 
} 

}

Answer 1

只要把这些线内做......而

int useroption; 
useroption = topmenu(); 

重新排列如下...

int useroption; 
     // excute while loop untill option is not 1-3 
     do 
     { 

      useroption = topmenu(); 

和你的程序将正常工作

完整的代码是在这里： http://pastebin.com/fCh0ttUY

Answer 2

人首先，设置useroption到0执行一些代码后。否则它将继续执行它。其次，ReadKey（）就在while语句之前。否则，你将无法读取输入。

Answer 3

问题是，尽管您再次显示topmenu y你永远不要重新分配有用的价值。

正如gypsyCoder所说，在do {} while（）块内移动菜单的显示将解决您的问题，因为它会导致循环中每次循环重新分配用途。