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

     > File Name: 41_ReverseWords.c

     > Author: Juntaran

     > Mail: JuntaranMail@gmail.com

     > Created Time: 2016年09月04日 星期日 16时18分34秒

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

 #include <stdio.h>

 // 反转单词

 void ReverseWord(char* left, char* right)

 {

     if (left== NULL || right==NULL)

         return;

     while (left < right)

     {

         char temp = *left;

         *left = *right;

         *right = temp;

         left ++;

         right --;

     }

 }

 void Reverse(char* str)

 {

     if (str == NULL)

         return;

     char* left = str;

     char* right = str;

     while (*(right+) != '\0')

         right++;

     // 先反转整个句子

     ReverseWord(left, right);

     // 再逐步反转每个单词

     left = str;

     right = str;

     while (*left != '\0')

     {

         if (*left == ' ')

         {

             left ++;

             right++;

         }

         else if (*right==' ' || *right=='\0')

         {

             ReverseWord(left, --right);

             left = ++right;

         }

         else

         {

             right ++;

         }

     }

 }

 int main()

 {

     char str[] = "I am a student. ";

     Reverse(str);

     printf("%s\n", str);

     return ;

 }