命名参数 named parameter

C#4.0引入了命名参数，它允许指定要使用哪个参数。

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

namespace NamedPara
{
    public static class WordProcessor
    {
        private const bool defaultval = false;

        public static List<string> GetWords(
            string sentence,
            bool capitalizwwords = false,
            bool reverseorder = defaultval,
            bool reverseWords = false
            )
        {
            List<string> words = new List<string>(sentence.Split(' '));

            return words;
        }
        
    }

    class Program
    {
        static void Main(string[] args)
        {
            string sentence = "can be assigned the values true false or null.";
            List<string> words;

            words = WordProcessor.GetWords(sentence);
            foreach (string s in words)
            {
                Console.Write(s);
                Console.Write(" ");
            }
            Console.Write("
");

            words = WordProcessor.GetWords(sentence, reverseWords: true, capitalizwwords:true);

            foreach (string s in words)
            {
                Console.Write(s);
                Console.Write(" ");
            }
            Console.Write("
");

            Console.ReadLine();
        }
    }
}