Linked list doesn't function properly - c

Question

I'm attempting to extract text from a text file using linked lists. My code so far:
#include <stdlib.h>
#include <string.h>
#define N 20
struct node
{
char * str;
struct node * node;
};
typedef struct node Node;
typedef Node * WordList;
typedef Node * Node_ptr;
void addtext(WordList * lst_ptr);
void report(WordList words);
Node * createnode(char *str);
int main(void)
{
WordList words = NULL;
addtext(&words);
report(words);
return 0;
}
Node * createnode(char *str)
{
Node_ptr newnode_ptr ;
newnode_ptr = malloc(sizeof (Node));
newnode_ptr -> str = NULL;
newnode_ptr -> node = NULL;
return newnode_ptr;
}
void addtext(WordList * lst_ptr)
{
FILE *fileinput;
char word[N];
char *pnt;
if ((fileinput = fopen("test.txt", "rt"))==NULL)
{
printf("Cannot open file. Please check if the file is in the right directory and you are giving the correct name.");
exit(EXIT_FAILURE);
}
while (fscanf(fileinput, "%19s", word) == 1)
{
Node * newnode = createnode(word);
if (*lst_ptr==NULL)
{
newnode->node = *lst_ptr;
*lst_ptr = newnode;
}
else
{
Node *iter;
for (iter = *lst_ptr; iter -> node != NULL; iter = iter -> node);
iter -> node = newnode;
}
pnt = strtok (word," ");
while (pnt != NULL)
{
newnode->str = pnt;
pnt = strtok (NULL, " ");
}
}
fclose(fileinput);
return ;
}
void report(WordList words)
{
if (words == NULL)
{
printf("\n") ;
return ;
}
printf("%s\n",words -> str);
report(words -> node);
return;
}
The text file I've made contains the following:
Hello
Bye
But the output of my program is:
Bye
(random characters)
Meaning that it prints the last word. My guess is that when I call report it point to the last element of the list and keeps going from there for as many times as the amount of words in the text file.
I also tried a different approach on the report function:
void report(WordList words)
{
Node * iter;
for (iter = words; iter!=NULL; iter = iter->node)
{
printf("%s\n", iter->str);
}
return;
}
But now it prints \n until the loop ends. Am I missing something simple or am I making a grave mistake?

Answer 1

The strtok() modifies the original string and returns pointers to elements of the original string. In this case the original string is stored in a local array char word[N];. The local array will vanish on returning the function addtext and refering the array from the function report after that is illegal.
To avoid this trouble, you should allocate some new regions and copy the string there. It can be done like this:
pnt = strtok (word," ");
while (pnt != NULL)
{
newnode->str = malloc(strlen(pnt) + 1); /* allocate a region (+1 for terminating null-character) */
if (newnode->str == NULL) /* check if allocation succeeded */
{
/* handle allocation failure */
exit(1);
}
strcpy(newnode->str, pnt); /* copy the string */
pnt = strtok (NULL, " ");
}

Answer 2

Simplified:
newnode->str = strdup(pnt);