class Test
    {
        delegate K proxy<T, K>(T t, K k); //泛型委托，注意返回值的写法，返回值的类型K先于其声明proxy<T,K>中的K，这是C#底层的事
        public static void Main()
        {
            proxy<int, string> pxy = varCat;
            proxy<int, int> padd = addTest;
            string s = pxy(10, "xyz");
            int sadd = padd(13, 12);

            var obj = new { ID = 10, age = 30, name = "tom" }; //匿名类，变量都是只读的
            proxy<int, int> paddEnonymous = delegate (int x, int y) //匿名函数
            {
                return x + y;
            };

            proxy<int, int> paddLambda = (int x, int y) =>//lambda表达式，相当于一种匿名函数
            {
                return x + y;
            };

        }

        public static string varCat(int i, string s)
        {
            return i + ": " + s;
        }
        
        public static int addTest(int x, int y)
        {
            return x + y;
        }