委托Action，Func，以及lambda的使用

class Program
    {
        delegate string del(int i);//自定义委托
        static public Action A;
        static public Action<int> B;
        static public Action<int, string> C;

        static public Func<string,string,string> fB;//第最后一个参数为返回
        static public calculate GetCal() => new calculate();//lambda方法定义
        
        static void Main()
        {
            del d = n => {
                string s = n + " World";
                return s;
            };
            Console.WriteLine(d(10));//执行

            GetCal();

            fB = (m,n) => { return m+n+"abc"; }; Console.WriteLine(fB("123","789"));
            A = () =>
            {
                Console.WriteLine("I'm A ");
            };

            B = (i) =>
            {
                Console.WriteLine("I'm B " + i);
            };

            C = (int i, string s) =>
            {
                Console.WriteLine("I'm C " + i + " " + s);
            };
           
            A();
            B(1);
            C(1, "a");
            testAction(() => { Console.WriteLine("run action"); });//执行action
            Console.ReadKey();
        }
        static void testAction(Action ac)
        {
            ac();
        }
    }