C# GOTO 在这个例子中是如何工作的(不符合预期)？

Question

这段 C# 代码很简单:

这段代码的场景:

当单词匹配时会产生意外的输出:

找到这个词找不到这个词found的值为:True

当单词不匹配时，它会产生预期的输出:

找不到这个词found的值为:False

    static void Main()
    {
        string[] words = { "casino", "other word" };

        Boolean found = false;
            foreach (string word in words)
            {
                if (word == "casino")
                {
                    found = true;
                    goto Found;
                }
            }

        if(!found)
        {
            goto NotFound;
        }

    Found: { Console.WriteLine("The word is found"); }
    NotFound: { Console.WriteLine("The word is not found"); }

        Console.WriteLine("The value of found is: {0}", found);

        Console.Read();
    }

Answer 1

goto 语句只是将执行移至该点。因此，在您的情况下，正在执行 Found，然后正在执行下一行 NotFound。

要使用 goto 解决此问题，您必须有第三个 goto，类似于 Continue。

static void Main()
{
    string[] words = { "casino", "other word" };

    Boolean found = false;

    foreach (string word in words)
    {
        if (word == "casino")
        {
            found = true;
            goto Found;
        }
    }

    if(!found)
    {
        goto NotFound;
    }

    Found: { Console.WriteLine("The word is found"); goto Continue; }
    NotFound: { Console.WriteLine("The word is not found"); }

    Continue:
    Console.WriteLine("The value of found is: {0}", found);

    Console.Read();
}

不过我更喜欢这样的东西:

static void Main()
{
    string[] words = { "casino", "other word" };

    Boolean found = false;

    foreach (string word in words)
    {
        if (word == "casino")
        {
            found = true;
            break;
        }
    }

    if(!found)
    {
        Console.WriteLine("The word is not found");
    }
    else
    {
        Console.WriteLine("The word is found");
    }

    Console.WriteLine("The value of found is: {0}", found);

    Console.Read();
}

甚至更好!

static void Main()
{
    string[] words = { "casino", "other word" };

    if (words.Contains("casino"))
    {
        Console.WriteLine("The word is found");
    }
    else
    {
        Console.WriteLine("The word is not found");
    }

    Console.Read();
}