while循环重复用户输入C＃

Question

在我的while循环中，它提示用户输入一个值，一旦输入值，便会使用某些方法。 我遇到的问题是，提示用户两次输入值（即要求输入A，B或X。用户输入值，然后程序再次要求输入A，B或X，而不执行正确的操作）。 输入后对其进行操作的任何帮助都将非常有用！

         class output
         {
         static void Main(string[] args)
         {
            char userInput;
            char upper;

            Accounts myAccounts = new Accounts();
            myAccounts.input();
            Console.WriteLine("Enter an A to search account numbers");
            Console.WriteLine("Enter a B to average the accounts");
            Console.WriteLine("Enter X to quit the program");
            Console.WriteLine("Enter an option --->");

            userInput = Convert.ToChar(Console.ReadLine());
            upper = char.ToUpper(userInput);

            while (upper != 'X')
            {

                if (upper == 'A')
                {
                    myAccounts.search();
                    Console.WriteLine("Enter an A to search account numbers");
                    Console.WriteLine("Enter a B to average the accounts");
                    Console.WriteLine("Enter X to quit the program");
                    Console.WriteLine("Enter an option --->");
                    userInput = Convert.ToChar(Console.ReadLine());
                    upper = char.ToUpper(userInput);
                }
                else if (upper == 'B')
                {
                    myAccounts.average();
                    Console.WriteLine("Enter an A to search account numbers");
                    Console.WriteLine("Enter a B to average the accounts");
                    Console.WriteLine("Enter X to quit the program");
                    Console.WriteLine("Enter an option --->");
                    userInput = Convert.ToChar(Console.ReadLine());
                    upper = char.ToUpper(userInput);
                }
                else
                    Console.WriteLine("You entered an incorrect option, please select new option");
                Console.WriteLine("Enter an A to search account numbers");
                Console.WriteLine("Enter a B to average the accounts");
                Console.WriteLine("Enter X to quit the program");
                Console.WriteLine("Enter an option --->");
                userInput = Convert.ToChar(Console.ReadLine());
                upper = char.ToUpper(userInput);
            }        
        }
    }

Answer 1

尝试像这样重新格式化主文件：

 static void Main(string[] args)
 {
    char userInput;
    char upper;

    Accounts myAccounts = new Accounts();
    myAccounts.input();

    do
    {

        Console.WriteLine("Enter an A to search account numbers");
        Console.WriteLine("Enter a B to average the accounts");
        Console.WriteLine("Enter X to quit the program");
        Console.WriteLine("Enter an option --->");
        userInput = Convert.ToChar(Console.ReadLine());
        upper = char.ToUpper(userInput);

        if (upper == 'A')
        {
            myAccounts.search();
        }
        else if (upper == 'B')
        {
            myAccounts.average();

        }
        else
            Console.WriteLine("You entered an incorrect option, please select new option");
    }   
    while (upper != 'X')     
}

它并不完美，但是是一个很好的起点。 基本上为什么两次出现提示是因为在进入while循环之前先显示菜单，然后在执行操作后再次显示菜单。 我提供的do while循环应该可以解决您的问题。