C#新特性

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace LocalApp.ConsoleApp
{
    class Program
    {
        delegate void LambdaHandler();

        static void Main(string[] args)
        {
            //Func 封装一个具有 1 - 4 个参数并返回 TResult 参数指定的类型值的方法。

            Func<int, string> func = delegate(int i) { return Convert.ToString(i * i); };
            Console.WriteLine(func(3));

            /**//******************************************/

            // lambda 表达式，i 参数
            Func<int, string> func2 = i => Convert.ToString(i * i);
            Console.WriteLine(func2(4));

            /**//******************************************/

            Func<string, string> func3 = a => a.ToUpper();

            string[] array = { "hebei","hubei","beijing","12" };

            IEnumerable<string> _array = array.Where<string>(b => b.EndsWith("i")); // array.Select(func3);

            foreach (string i in _array)
                Console.WriteLine(i);

            /**//******************************************/

            Func<string, string, string, string, string> __func = (a, b, c, d) => { return a + "_" + b + "_" + c + "_" + d; };

            Console.WriteLine(__func("h","e","l","lo"));

            /**//******************************************/


            Func<string> __func2 = () => "123456";

            Console.WriteLine(__func2());

            /**//******************************************/

            LambdaHandler lam = () => Console.WriteLine( "1111111111");

            lam += () => Console.WriteLine("22222222222");

            lam();

            /**//******************************************/
            
            //扩展方法
            string extTest = "hello world";

            Console.WriteLine(extTest.WordCount());

            foreach(string i in extTest.WordSplit())
            {
                Console.WriteLine(i);
            }

            /**//******************************************/
            Console.ReadKey(true);
        }
    }

    /**//// <summary>
    /// 扩展方法
    /// </summary>
    public static class Extensions
    {
        public static int WordCount(this String str)
        {
            return str.Split(new char[] { ' ', '.', '?' }, StringSplitOptions.RemoveEmptyEntries).Length;
        }

        public static string[] WordSplit(this String str)
        {
            return str.Split(new char[] {' ','.','?' }, StringSplitOptions.None);
        }
    }
}