如何将文件中的字符串加载到 C 中的链接列表中？

Question

...I am relatively new to using stack overflow, so feel free to let me know if there is anything wrong with this post.

I am attempting to load a couple of words from a file called dict into a linked list. When I manually try to print out the words that I've loaded, it just prints out the last word a bunch of times. Does anyone see what I'm doing wrong here?

CELL* head = malloc(sizeof(CELL));
CELL* ptr;

while (fscanf(dict, "%s", buffer) != EOF)
{
    ptr = malloc(sizeof(CELL));
    ptr->word = buffer;
    ptr->next = NULL;

    ptr->next = head;
    head = ptr;
}

CELL *tmp;
printf("%s", head->word);
printf("%s", head->next->word);
printf("%s", head->next->next->word);

Answer 1

You are pointing every node to the buffer. You need to make a copy instead.

You might want to replace this line

ptr->word = buffer;

By these two:

    ptr->word = malloc(strlen(buffer) + 1);
    strcpy(ptr->word, buffer);

As mentioned in the comments, the last element of your list won't point to NULL, it will be whatever value that was in the memory returned by CELL* head = malloc(sizeof(CELL)); .

You could initialize head to NULL and remove the line ptr->next = NULL; to fix that.

Answer 2

The issue here is that you are overwritting the data in head and its self referencing itself

Lets assume the content of file as below

Hi, how are you?

head is empty at first pass, when it enters the loop and ptr gets the word as "Hi," and you are setting the next to null once done your are point the next to head. but then you are overwritting the head with ptr so its self referencing itself and it gets overwritten.

As the name of variable suggest, head should be one using the next to point to the next item in linked list.