Question

我试图制作一个简单的程序，询问用户是否要输入他们的名字。我使用了do-while循环来执行此操作。如果答案为“ y”，则程序将打印文本并询问用户名称。如果答案为“ n”，则打印文本。在这两种情况下，循环都结束。如果用户输入的不是“ y”或“ n”，则循环重复并要求输入正确的值。我的问题是，只要有人输入以字母“ y”开头的任何字符串，例如“ yes”或“ yeetjasdk”。发生这种情况时，代码将打印文本以询问用户正确的输入，但是，循环退出，程序结束。对于以'n'开头的单词，不会发生这种情况。

do  {                                                                           //Keep running loop until user
            Console.Write("Welcome. Do you want to tell us your name? (y/n): ");    //enters either y or n.
            answer = Console.ReadLine();                                             //Ask user for input.
                if (answer == "y") {
                    Console.Write("What is your name: ");
                    userName = Console.ReadLine();  
                    Console.WriteLine("Welcome, {0}", userName);
                }
                else if (answer == "n") { Console.WriteLine("Acknowledged."); }
                else { Console.WriteLine("Sorry, I didn't catch that."); }
        } while((result = string.Compare(answer, "y", true)) < 0 || (result = string.Compare(answer, "n", true)) < 0);

Answer 1

这行对我来说真的很奇怪：

while ((result = string.Compare(answer, "y", true)) < 0 || (result = string.Compare(answer, "n", true)) < 0);

string.Compare()根据排序顺序执行大于/小于/等于比较。那似乎不是您想要的。

为什么不使用更简单的方法？如：

while (answer != "y" && answer != "n")

或者更好的是，一旦知道答案有效，就退出循环。这样一来，您无需再次检查条件，就可以确保逻辑一致。

while (true)
{                                                                                         
    Console.Write("Welcome. Do you want to tell us your name? (y/n): ");
    answer = Console.ReadLine();
    if (answer == "y") 
    {
        Console.Write("What is your name: ");
        userName = Console.ReadLine();  
        Console.WriteLine("Welcome, {0}", userName);
        break; // <-- exit the loop
    }
    if (answer == "n")
    {
        Console.WriteLine("Acknowledged.");
        break;  //<-- exit the loop
    }
    Console.WriteLine("Sorry, I didn't catch that."); }
}

C＃做while循环以y开头的任何单词都会触发y / n检查并破坏循环

1 个答案: