第一次用C语言把数据写入文件中

在文件中创建一个txt文件后，就可以使用程序了

本程序从正文文件text.txt中读入一篇英文短文，统计该短文中不同单词及出现次数，并按词典编辑顺序将单词及出现次数输出到正文文件word.txt中。

程序用一棵有序二叉树存储这些单词及其出现的次数，边读入边建立，然后中序遍历该二叉树，将遍历经过的二叉树上的结点的内容输出。

#include "stdafx.h"
# include <stdio.h>
# include <malloc.h>
# include <ctype.h>
# include <string.h>
# define   INF        "text.txt"
# define   OUTF     "word.txt"
typedef struct treenode {
       char *word;
       int    count;
       struct treenode *left, *right;
} BNODE;
int getword(FILE *fpt, char *word)
{     char c;
       c=fgetc(fpt);
       if ( c == EOF)
              return 0;
       while(!(tolower(c) >= 'a' && tolower(c) <= 'z'))
       {     c=fgetc(fpt);
              if ( c == EOF)
                     return 0;
       }  /* 跳过单词间的所有非字母字符 */
       while(tolower(c) >= 'a' && tolower(c) <= 'z')
       {     *word++ = c;
              c = fgetc(fpt);
       }
       *word = '\0';
       return 1;
}
void binary_tree(BNODE **t, char *word)
{     BNODE   *ptr, *p; int compres;
       p = NULL;
    ptr=*t;
       while (ptr)  /* 寻找插入位置 */
    {     compres=strcmp(word,ptr->word); /* 保存当前比较结果 */
              if (!compres)
     {      ptr->count++ ;
     return; }
              else
              {       p=ptr ;
                     ptr = compres>0 ? ptr->right : ptr->left;
              }
       }
       ptr = (BNODE *)malloc(sizeof(BNODE));
       ptr->left = ptr->right = NULL;
       ptr->word = (char *)malloc(strlen(word)+1);
       strcpy(ptr->word, word);
       ptr->count = 1;
       if (p == NULL)
            *t=ptr ;
       else if (compres > 0)
              p->right = ptr;
       else
              p->left = ptr;
}
void midorder(FILE *fpt, BNODE *t)
{     if ( t == NULL )
              return;
       midorder(fpt, t->left);
       fprintf(fpt, "%s %d\n", t->word, t->count);
       midorder(fpt, t->right);
}
void main()
{     FILE       *fpt;  char word[40];
       BNODE   *root=NULL;
       if ((fpt=fopen(INF, "r")) == NULL)
       {     printf("Can't open file %s\n", INF);
              return;
       }
       while(getword(fpt, word) == 1)
              binary_tree( &root, word );
       fclose(fpt);
       fpt = fopen(OUTF, "w");
       if (fpt == NULL)
       {     printf("Can't open file %s\n", OUTF);
              return;
       }
       midorder(fpt, root);
       fclose(fpt);
}