Having problems with assert in c - c

Question

I'm working on a programming assignment at the moment where the objective is to compare hashing strategies. For the main part of the program, the user is allowed to use it with options (using getopt).
The problem I'm trying to solve is that I have an option that tells the program to scan through a dictionary and compares words given in from stdin with the words in the dictionary, and prints the words with differences (words from stdin). Here is a code partial:
if (flag_c) {
while (getword(word, sizeof word, fopen(filename, "r")) != EOF) {
start = clock();
if (htable_search(h, word) == 0) {
fprintf(stderr, "%s\n", word);
unknown_word_count++;
}
search_time += (clock() - start) / (double) CLOCKS_PER_SEC;
}
printf("Fill time : %f\n", fill_time);
printf("Search time : %f\n", search_time);
printf("Unknown words = %d\n", unknown_word_count);
}
Now I think the problem lies in the while loop conditon. The getword function is defined below:
int getword(char *s, int limit, FILE *stream) {
int c;
char *w = s;
assert(limit > 0 && s != NULL && stream != NULL);
/* skip to the start of the word */
while (!isalnum(c = getc(stream)) && EOF != c)
;
if (EOF == c) {
return EOF;
} else if (--limit > 0) { /* reduce limit by 1 to allow for the \0 */
*w++ = tolower(c);
}
while (--limit > 0) {
if (isalnum(c = getc(stream))) {
*w++ = tolower(c);
} else if ('\'' == c) {
limit++;
} else {
break;
}
}
*w = '\0';
return w - s;
}
When I run the program I get the error:
Test: mylib.c:10: getword: Assertion `limit > 0 && s != ((void *)0) && stream != ((void *)0)' failed.
Aborted (core dumped)
I'm really not too sure why this is happening. Any ideas?

Answer 1

You are using fopen in the while loop:
while (getword(word, sizeof word, fopen(filename, "r")) != EOF) {
Does getword close the FILE*? If not you have a lot of open file handles.
What you probably need is:
Open the file before the start of the while loop.
Use the FILE* in the loop.
Close the file after you get out of the while loop.
FILE* fp = fopen(filename, "r");
if ( fp == NULL )
{
// Deal with error condition.
}
while (getword(word, sizeof word, fp) != EOF) {
start = clock();
if (htable_search(h, word) == 0) {
fprintf(stderr, "%s\n", word);
unknown_word_count++;
}
search_time += (clock() - start) / (double) CLOCKS_PER_SEC;
}
fclose(fp);