将文本文件中的单词插入C语言的树中 [英] Inserting word from a text file into a tree in C

问题描述

在过去的两天里，我一直遇到一个奇怪的问题，但现在还无法解决.我正在尝试从2个文本文件中获取单词，并将这些单词添加到树中.我选择的获取单词的方法在这里引用: 将文本文件拆分为C .

I have been encountering a weird problem for the past 2 days and I can't get to solve it yet. I am trying to get words from 2 texts files and add those words to a tree. The methods I choose to get the words are refereed here: Splitting a text file into words in C.

我用来将单词插入树中的函数如下:

The function that I use to insert words into a tree is the following:

void InsertWord(typosWords Words, char * w)
{
   int error ;
   DataType x ;
   x.word = w ;
   printf(" Trying to insert word : %s \n",x.word );
   Tree_Insert(&(Words->WordsRoot),x, &error) ;
   if (error)
   {
       printf("Error Occured \n");
   }
}

如发布的链接中所述，当我尝试将文本文件中的单词导入树中时，出现发生错误".再次提供功能:

As mentioned in the link posted , when I am trying to import the words from a text file into the tree , I am getting "Error Occured". For once again the function:

文本文件:

a

aaah

aaahh

char this_word[15];
while (fscanf(wordlist, "%14s", this_word) == 1) 
{
   printf("Latest word that was read: '%s'\n", this_word);
   InsertWord(W,this_word);
}

但是当我通过以下方式插入完全相同的单词时，它就可以正常工作.

But when I am inserting the exact same words with the following way , it works just fine.

    for (i = 0 ; i <=2 ; i++)
    {
    if (i==0)
        InsertWord(W,"a");
    if (i==1)
        InsertWord(W,"aaah");
    if (i==2)
        InsertWord(W,"aaahh");
    }

这证明了树的功能可以正常工作，但是我不知道当时发生了什么，我已经连续调试了两天，但仍然无法弄清它.有什么想法吗?

That proves the tree's functions works fine , but I can't understand what's happening then.I am debugging for straight 2 days and still can't figure it. Any ideas ?

推荐答案

当您使用

char this_word[15];
while (fscanf(wordlist, "%14s", this_word) == 1) 
{
   printf("Latest word that was read: '%s'\n", this_word);
   InsertWord(W,this_word);
}

您总是在为字符串重复使用相同的内存缓冲区.这意味着您这样做

you are always reusing the same memory buffer for the strings. This means when you do

x.word = w ;

您始终存储相同的地址.而且每次读取都会重新定义所有已经存储的单词，从而基本上破坏了数据结构.

you are ALWAYS storing the SAME address. And every read redefine ALL already stored words, basically corrupting the data structure.

尝试将char this_word[15];更改为char *this_word;并放置一个this_word = malloc(15); in the beggining of the while`循环，使其为每次迭代分配一个新的缓冲区.看起来像

Try changing the char this_word[15]; to char *this_word; and placing a this_word = malloc(15);in the beggining of thewhile` loop instead, making it allocate a new buffer for each iteration. So looking like

char *this_word;
while (fscanf(wordlist, "%14s", this_word) == 1) 
{
   this_word = malloc(15);
   printf("Latest word that was read: '%s'\n", this_word);
   InsertWord(W,this_word);
}

正如迈克尔·沃尔兹(Michael Walz)所建议的那样，strdup(3)也解决了眼前的问题.

As suggested by Michael Walz a strdup(3) also solves the immediate problem.

当然，当树完成后，您还将释放.word元素.

Of course you will also have do free up the .word elements when finished with the tree.

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