Question

所以我对C＃完全陌生，事实上我刚开始学习半小时前的语法。

到目前为止，我所做的只是搞乱语法，并制作了几行代码的交互式输入程序。当我完成输入我的代码并想运行该程序时，它给了我一个错误。

        Console.Write("What is your name?: ");
        string name = Console.ReadLine();    //'name' used here
        Console.WriteLine("Hello " + name);
        Console.ReadLine();

        Console.Write("How old are you?: ");
        int age = Convert.ToInt32(Console.ReadLine());
        Console.WriteLine("So you're name is " + name + " and you are " + age + " years old?");
        Console.ReadLine();

        Console.Write("Tell me, yes or no?: ");
        string answer = Console.ReadLine();


        if (answer == "no" || answer == "No")

        { 
           Console.Write("Ahh okay, what was your name again?: ");
           string name  = Console.ReadLine();    //'name' used here
        }

＆＃34;名为＆＃39;名称＆＃39;的本地或参数不能在此范围内声明......＆＃34;

我知道问题必须出在最后一行代码中，我在其中为字符串命名了一个新值＆＃39; name＆＃39;。我确信这在PHP中是可行的，为变量赋值。正如我所说，我对C＃全新，我想知道是否有办法做到这一点？

Answer 1

那是因为你重新声明了两次变量名。只需删除字符串声明。您也无法在子范围中定义相同的变量名称。（{ }之间）

   if (answer == "no" || answer == "No")

    { 
       Console.Write("Ahh okay, what was your name again?: ");
       name = Console.ReadLine();
    }

Answer 2

只是你不能两次声明一个变量。当您键入string name时，您正在声明它。请尝试如下：

    string name;
    Console.Write("What is your name?: ");
    name = Console.ReadLine();
    Console.WriteLine("Hello " + name);
    Console.ReadLine();

    Console.Write("How old are you?: ");
    int age = Convert.ToInt32(Console.ReadLine());
    Console.WriteLine("So you're name is " + name + " and you are " + age + " years old?");
    Console.ReadLine();

    Console.Write("Tell me, yes or no?: ");
    string answer = Console.ReadLine();


    if (answer == "no" || answer == "No")

    { 
       Console.Write("Ahh okay, what was your name again?: ");
       name  = Console.ReadLine();
    }

希望这有帮助。

Answer 3

问题是您在此行声明了字符串变量name：

string **name** = Console.ReadLine();

然后，在if语句中，您尝试再次声明它。如果你的意思是“重用”同一个变量，只需删除字符串部分（告诉c＃你声明一个字符串类型的变量）：

name = Console.ReadLine();

玩得开心！

Answer 4

名称已经宣布。要分配新值，您无需指定变量类型。因此，请在最后一行string之前删除name。

Answer 5

尝试删除“字符串”？

    { 
       Console.Write("Ahh okay, what was your name again?: ");
       **name**  = Console.ReadLine();
    }

C＃为变量分配新值

5 个答案: