检测到无法访问的代码C#(绝对初学者)

Question

你能解释我应该如何避免这个警告:在Visual Studio 2010 Express中"检测到无法访问的代码"？我正在从手册中学习C#.这是一个创建简单方法的练习.我正如书中所写的那样进入这个例子.谢谢.

public class Multiply 
{
    //Multiplies argument by 4 

    public static int MultiplyBy4(int aNumber)
    {
        return 4 * aNumber;
        //Shows ways of passing various arguments to a method public static void Main
        int x = 7;
        int y = 20;
        int z = -3;
        int result = 0;

        result = MultiplyBy4(x);
        Console.WriteLine("Passsing a variable, x : {0}", result);

        result = MultiplyBy4(y + 2);
        Console.WriteLine("Passing an expression, Y + 2: {0}", result);

        result = 5 + MultiplyBy4(z);
        Console.WriteLine("Using MultiplyBy4 in an expression: {0}", result);
        Console.ReadLine();
    }
 }

我不理解手册评论:"在使用参数和返回值创建方法后,显示将各种参数传递给方法public static void Main"的方法.如何使MultiplyBy4方法将x,y,z识别为"aNumber"？也许这是一个迟钝的问题,但我被困在这里.谢谢.

Answer 1

注释行混乱并包含Main方法的定义.代码应为:

    public class Multiply 
{
        //Multiplies argument by 4 
        public static int MultiplyBy4(int aNumber)
        {
            return 4 * aNumber;
        }

        //Shows ways of passing various arguments to a method
        public static void Main(string[] args)
        {
                int x = 7;
                int y = 20;
                int z = -3;
                int result = 0;

                result = MultiplyBy4(x);
                Console.WriteLine("Passsing a variable, x : {0}", result);

                result = MultiplyBy4(y + 2);
                Console.WriteLine("Passing an expression, Y + 2: {0}", result);

                result = 5 + MultiplyBy4(z);
                Console.WriteLine("Using MultiplyBy4 in an expression: {0}", result);
                Console.ReadLine();
            }
 }