Question

 class Program
 {
    static void Main(string[] args)
    {
        string Studentname;
        string retry = "No";

        Console.WriteLine("What is the Student's name? ");

        while (retry != "No")
             Console.WriteLine("What is the Student's name? ");

        Studentname = Console.ReadLine();

        switch (Studentname) {
            case "George":
                Console.WriteLine("Yes in the list");
                Console.ReadLine();
                break;

            case "Goblin":
                Console.WriteLine("Yes in the list");
                Console.ReadLine();
                break;

            case "Peter":
                Console.WriteLine("Yes in the list");
                Console.ReadLine();
                break;

            case "TJ":
                Console.WriteLine("Yes in the list");
                Console.ReadLine();
                break;

            default:
                Console.WriteLine("Not in the list");
                Console.WriteLine("Would you like to retry?");
                retry = Console.ReadLine();
                break;
        }
    }
}

如果答案不正确，我试图循环使用case语句，但是语句总是会中断，我无法循环。我该如何解决这个问题？

Answer 1

关键字“break”只会突破第一个代码块（它位于{...}之间的空间）。交换机的中断不应该干扰你的while循环。

问题是你的while循环之后没有括号，因此它只会直接作用于该行。

以下可能就是你要找的东西。

class Program
{
    static void Main(string[] args)
    {
        string Studentname;
        string retry = "No";

        Console.WriteLine("What is the Student's name? ");
        do
        {
            Console.WriteLine("What is the Student's name? ");
            Studentname = Console.ReadLine();

            switch (Studentname)
            {
                case "George":
                    Console.WriteLine("Yes in the list");
                    //Console.ReadLine();
                    break;
                case "Goblin":
                    Console.WriteLine("Yes in the list");
                    //Console.ReadLine();
                    break;
                case "Peter":
                    Console.WriteLine("Yes in the list");
                    //Console.ReadLine();
                    break;
                case "TJ":
                    Console.WriteLine("Yes in the list");
                    //Console.ReadLine();
                    break;
                default:
                    Console.WriteLine("Not in the list");
                    Console.WriteLine("Would you like to retry?");
                    retry = Console.ReadLine();
                    break;
            }
        } while (retry != "No");
    }
}

编辑：你的while循环也从未输入过。您将“重试”设置为“否”，然后检查它是否不是“否”。要解决这个问题，您可以使用“do ... while（）”循环，它总是循环至少一次，或者您可以将“重试”的第一个分配更改为除“否”之外的任何内容。

编辑2：@Kason是正确的。如果找到名字，我没有意识到你的实际目标是退出。如果是这种情况，那么“do ... while（）”是您的最佳选择。

Answer 2

相反，你可以使用这个简单的LINQ方法：

O(n + m) = O(n)

但是它没有用，因为你已经忘了把string Studentnames[] = new string[] { "George", "Goblin", "Peter", "TJ" } while (retry != "No") { if (Studentnames.Contains(Studentname) { Console.WriteLine("Yes in the list"); Console.ReadLine(); } else { Console.WriteLine("Not in the list"); Console.WriteLine("Would you like to retry?"); retry = Console.ReadLine(); } }放在while语句中。

Answer 3

在while语句后面添加一个左大括号，在代码底部添加一个匹配的右大括号。

Answer 4

while循环开头后没有花括号。这意味着while语句仅适用于紧随其后的行。

while (retry != "No")
    Console.WriteLine("What is the Student's name? ");

如上所述，retry以＆＃34; No＆＃34;开始。因此，当评估while条件时，它是错误的。以下行永远不会执行，因为它只能在retry != "No"时执行。

如果希望while应用于一个语句块，请将它们放在大括号中。

while (retry != "No")
{
    //Everything inside these braces will execute if retry != "No".
    //If it gets to the end and retry still != "No" then it will repeat.
    //You'd most likely want to do something inside this loop sooner or
    //later that changes retry to something else so that the loop can
    //end. Or you can use "break" to exit the loop.
}

如何在C＃中循环切换语句

4 个答案: