Unable to save string into pointer to array - c

Question

I'm trying to save certain words into a pointer to an array (**valid_words), but I am running into an issue I do not understand. Below is the function I am trying to utilize, end result is to have valid_words contains all the valid words according to the condition when iline and dline are equal.
void CheckFile(char *input_file, char *dictionary_file, char *output_file, char **valid_words)
{
/* Open files as read or append */
FILE *input, *dictionary, *output;
input = fopen(input_file, "r");
dictionary = fopen(dictionary_file, "r");
output = fopen(output_file,"a");
int word_count = 0;
/* Read from files */
if (input != NULL && dictionary!= NULL)
{
char *iline = malloc(MAXSIZE*sizeof(char));
char *dline = malloc(MAXSIZE*sizeof(char));
while (fgets (iline, sizeof iline, input) != NULL)
{
while (fgets (dline, sizeof dline, dictionary) != NULL)
{
trimwhitespace(iline);
trimwhitespace(dline);
if (strcasecmp(iline, dline) == 0 )
{
fprintf(output, "%s\n",iline);
valid_words[word_count] = iline;
printf("Word Count: %d\n", word_count);
printf("At Zero: %s\n", valid_words[0]);
printf("Valid Word: %s\n", valid_words[word_count]);
printf("Actual Word: %s\n", iline);
word_count++;
}
}
rewind(dictionary);
}
fclose(input);
fclose(dictionary);
fclose(output);
free(iline);
free(dline);
}
else
{
printf("An error has occured\n");
}
}
The current output I am getting is
Word Count: 0
At Zero: miles
Valid Word: miles
Actual Word: miles
Word Count: 1
At Zero: limes
Valid Word: limes
Actual Word: limes
Word Count: 2
At Zero: smile
Valid Word: smile
Actual Word: smile
Word Count: 3
At Zero: slime
Valid Word: slime
Actual Word: slime
I am expecting At Zero: to always output "miles", but this is not happening.
After the function has been called printing valid_words[i] results in nothing being printed out.
I will really appreciate it if someone can help me out, and am very open to any criticism. You can find the full implementation here at http://pastebin.com/TjxLRVaC
Thank you.

Answer 1

The answer to why it doesn't work is -
valid_words[word_count] = iline;
You should use either strcpy after ensuring that the element in valid_words can hold up to MAXSIZE characters or use strncat (NB: not strncpy) after ensuring that the first (really zeroth) character in the element in valid_words that you are inserting is '\0'.
Some observations:
Assuming MAXSIZE is a #defined constant, this is better -
char iline[MAXSIZE];
char dline[MAXSIZE;
than the malloc calls that you have (by the way, sizeof(char) is one by definition.)
Likewise, you are better off changing the last parameter of CheckFile to char valid_words[][MAXSIZE] (and thus changing the arguments in all the calls to CheckFile).
Hope this helps.