学步园

using System;
using System.Collections.Generic;
namespace ReverWords
{
    class MainClass
    {
        public static void Main(string[] args)
        {
            Console.WriteLine(ReverseWords("Hello World"));
            Console.Read();
        }
        public static string ReverseWords(string array)
        {
             if (string.IsNullOrEmpty(array))
             {
                  throw new ArgumentException("");
             }
             int arrLen = array.Length;
             char[] strNew = new char[arrLen + 1];
             
             //全部反转 
             for (int index = 0; index < arrLen; index++)
             {
                 strNew[index] = array[arrLen - 1 - index];
             }
             strNew[arrLen] = ' '; //为了复原最后一个单词，添加一个辅助空格 
             int iStart = 0, iEnd = 0;
             char tmpChar;+
             //复原单词 
             for (int Index = 0; Index < arrLen + 1; Index++)
             {
                //Index指向空格 
                if (strNew[Index] == ' ')
                {
                    iEnd = Index - 1;
                    while (iStart < iEnd)
                    {
                        tmpChar = strNew[iStart];
                        strNew[iStart] = strNew[iEnd];
                        strNew[iEnd] = tmpChar;
                        iStart++;
                        iEnd--;
                    }
                        iStart = Index + 1;//跳过空格 
                }
                else if (strNew[Index] == '!' | strNew[Index] == ',' | strNew[Index] == '.' | strNew[Index] == ';')
                {
                   iStart = Index + 1;//跳过标点 
                }
            }
            //合成字符串 
            array = string.Empty;
            for (int index = 0; index < strNew.Length - 1; index++)//去掉辅助的空格 
            {
               array += strNew[index];
            }
            return array;
       }
    }
}