get line in the text for each word - c

Question

The following program prints the word frequency in a file. I am trying to save for each word in the text file, which line/lines appeared and how many times in total in the whole file. It counts how many times it appeared but I can't get which lines of the txt file.
There is a problem with int lines[]. The ouput of the program gives
segmentation fault
#define MAXWORDS 10000
#define MAXSTRING 100
/* structure holding word frequency information */
typedef struct _word {
char s[MAXSTRING]; /* the word */
int count; /* number of times word occurs */
int lines[1000];
} word;
void insert_word (word *words, int *n, char *s, int no) {
int i;
/* linear search for the word */
for (i=0; i<*n; i++) if (strcmp (s, words[i].s) == 0) {
/* found it? increment and return. */
words[i].count++;
words[i].lines[words[i].count]=no;
printf("%d", no);
return;
}
/* error conditions... */
if (strlen (s) >= MAXSTRING) {
fprintf (stderr, "word too long!\n");
exit (1);
}
if (*n >= MAXWORDS) {
fprintf (stderr, "too many words!\n");
exit (1);
}
/* copy the word into the structure at the first available slot,
* i.e., *n
*/
strcpy (words[*n].s, s);
/* this word has occured once up to now, so count = 1 */
words[*n].count = 1;
words[*n].lines[words[*n].count]=no;
/* one more word */
(*n)++;
}
...........
int main () {
word words[MAXWORDS];
char s[1000];
int i, n, m;
n = 0;
FILE* file = fopen("test.txt", "r");
/* read all the words in the file... */
int no=1;
while (fgets(s, sizeof(s), file)) {
scanf ("%s", s);
insert_word (words, &n, s,no);
no=no+1;
}
}
fclose(file);
qsort((void *) words, n, sizeof (word),
(int (*) (const void *, const void *)) wordcmp);
if (n < 20)
m = n;
else
m = 20;
for (i=0; i<m; i++)
printf ("%s\t[%d] {%d} \n", words[i].s, words[i].count, words[i].lines);
}

Answer 1

Here's a solution with dynamic memory allocation:
typedef struct _word {
char *s; /* the word */
int count; /* number of times word occurs */
int *line_numbers; // Array of line numbers
int num_line_numbers; // Size of the array of line numbers
} word;
// Creating a struct to hold the data. I find it's easier
typedef struct {
word *words; // The array of word structs
int num_words; // The size of the array
} word_list;
void insert_word (word_list *words, char *s, int line_number)
{
/* linear search for the word */
for (int i = 0; i < words->num_words; i++) {
if (strcmp (s, words->words[i].s) == 0) {
/* found it? increment and return. */
words->words[i].count++;
// See if it already appeared in this line
if (words->words[i].line_numbers[words->words[i].num_line_numbers - 1] == line_number) {
return;
}
// New line number. Increase the line number array by one
int *tmp = realloc(words->words[i].line_numbers, sizeof(int) * (words->words[i].num_line_numbers + 1));
if (NULL == tmp) exit(0);
words->words[i].line_numbers = tmp;
// Add the line number to the array
words->words[i].line_numbers[words->words[i].num_line_numbers] = line_number;
words->words[i].num_line_numbers += 1;
return;
}
}
/* error conditions... */
....
// Increase the size of the word array by one.
word *tmp = realloc(words->words, sizeof(word) * (words->num_words + 1));
if (tmp == NULL) exit(0);
words->words = tmp;
/* copy the word into the structure at the first available slot,
* i.e., *n
*/
words->words[words->num_words].s = malloc(strlen(s) + 1);
strcpy(words->words[words->num_words].s, s);
/* this word has occurred once up to now, so count = 1 */
words->words[words->num_words].count = 1;
words->words[words->num_words].line_numbers = malloc(sizeof(int));
words->words[words->num_words].line_numbers[0] = line_number;
words->words[words->num_words].num_line_numbers = 1;
words->num_words += 1;
}
bool remove_word(word_list *words, const char *word_to_delete)
{
for (int i = 0; i < words->num_words; i++) {
if (0 == strcmp(words->words[i].s, word_to_delete)) {
// TODO: handle special case where there is only 1 word in list
// Calc number of words after found word
int number_of_words_to_right = words->num_words - i - 1;
// Free mem
free(words->words[i].s);
free(words->words[i].line_numbers);
// Copy remaining words
memcpy(&words->words[i], &words->words[i + 1], sizeof(word) * number_of_words_to_right);
// Resize the array (technically not required)
word *tmp = realloc(words->words, sizeof(word) * --words->num_words);
if (NULL == tmp) exit(0);
words->words = tmp;
return true;
}
}
return false;
}
And in main()
word_list *words = malloc(sizeof(word_list));
if (NULL == words) exit(0);
memset(words, 0, sizeof(word_list));
....
/* read all the words in the file... */
char s[1000];
int line_number = 1;
while (fgets(s, sizeof(s), file)) {
char *word = strtok(s, " ");
while (word != NULL) {
size_t len = strlen(word);
if (len > 0 && word[len - 1] == '\n') word[--len] = 0;
insert_word(words, word, line_number);
word = strtok(NULL, " ");
}
line_number += 1;
}
fclose(file);
for (int i = 0; i < words->num_words; i++) {
printf("%s\t\t[%d] {", words->words[i].s, words->words[i].count);
for (int j = 0; j < words->words[i].num_line_numbers; j++) {
if (j != 0) printf(",");
printf("%d", words->words[i].line_numbers[j]);
}
printf("}\n");
}
// It's good practice to always free mem. It's super not important
// in this app since the OS will do it when you exit
for (int i = 0; i < words->num_words; i++) {
free(words->words[i].s);
free(words->words[i].line_numbers);
}
free(words->words);
free(words);