class Ch06Ex05

    {

        //委托的声明非常类似于函数，但不带函数体，且要使用delegate关键字。

        //委托的声明指定了一个返回类型和一个参数列表。

        delegate double ProcessDelegate(double a,double b);//返回类型是double,参数列表：两个double变量a和b

        static double Multiply(double x,double y)

        {

            return x * y;

        }

        static double Divide(double m, double n)

        {

            return m / n;

        }

        public static void Method()

        {

            ProcessDelegate process;//在定义了委托后，就可以声明该委托类型的变量。

            process = new ProcessDelegate(Multiply);//把委托变量初始化为与委托有相同返回类型和参数列表的函数引用。

            Console.WriteLine("Multiply(100,10)={0}", process(, ));//使用委托变量调用这个函数，就像该变量是一个函数一样

            process = new ProcessDelegate(Divide);//把委托变量初始化为与委托有相同返回类型和参数列表的函数引用。

            process(, );//使用委托变量调用这个函数，就像该变量是一个函数一样

            Console.WriteLine("Divide(100,10)={0}", process(, ));

        }

    }

 class Program

    {

        /// <summary>

        /// 主函数

        /// </summary>

        /// <param name="args"></param>

        static void Main(string[] args)

        {

            Chapter06.Ch06Ex05.Method();

            Console.Read();

        }

    }

class Test

{

    delegate void TestDelegate(string s);

    static void M(string s)

    {

        Console.WriteLine(s);

    }

    static void Main(string[] args)

    {

        // Original delegate syntax required

        // initialization with a named method.

        TestDelegate testDelA = new TestDelegate(M);

        // C# 2.0: A delegate can be initialized with

        // inline code, called an "anonymous method." This

        // method takes a string as an input parameter.

        TestDelegate testDelB = delegate(string s) { Console.WriteLine(s); };

        // C# 3.0. A delegate can be initialized with

        // a lambda expression. The lambda also takes a string

        // as an input parameter (x). The type of x is inferred by the compiler.

        TestDelegate testDelC = (x) => { Console.WriteLine(x); };

        // Invoke the delegates.

        testDelA("Hello. My name is M and I write lines.");

        testDelB("That's nothing. I'm anonymous and ");

        testDelC("I'm a famous author.");

        // Keep console window open in debug mode.

        Console.WriteLine("Press any key to exit.");

        Console.ReadKey();

    }

}

/* Output:

    Hello. My name is M and I write lines.

    That's nothing. I'm anonymous and

    I'm a famous author.

    Press any key to exit.

 */