编写函数reverse（s），将字符串s中的字符顺序颠倒过来。使用该函数编写一个程序，每次颠倒一个输入行中的字符顺序。
#include <stdio.h>
   #define MAXLINE 1000   /* maximum input line length */
  int getline(char line[], int maxline);
   void copy(char to[], char from[]);
   /* print the longest input line */
   main()
   {
       int len;            /* current line length */
       int max;            /* maximum length seen so far */
       char line[MAXLINE];    /* current input line */
       char longest[MAXLINE]; /* longest line saved here */
       max = 0;
       while ((len = getline(line, MAXLINE)) > 0)
           if (len > max) {
               max = len;
               copy(longest, line);
           }
       if (max > 0)  /* there was a line */
           printf("%s", longest);
       return 0;
   }
   /* getline:  read a line into s, return length  */
   int getline(char s[],int lim)
   {
       int c, i;
       for (i=0; i < lim-1 && (c=getchar())!=EOF && c!='\n'; ++i)
           s[i] = c;
       if (c == '\n') {
           s[i] = c;
           ++i;
       }
       s[i] = '\0';
       return i;
   }
   /* copy:  copy 'from' into 'to'; assume to is big enough */
   void copy(char to[], char from[])
   {
       int i;
       i = 0;
       while ((to[i] = from[i]) != '\0')
           ++i;
   }

我的意思是你运用下面类似的代码编写，有串流的。。这个不当之处请见谅。。。

也不是很难哈，但是就是不会用串流。。。