C program to find word frequency - c

Question

I have a C program that will count the amount of words in each file given on the command line. I now need to make it count how many times each word appears. Here is my code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#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 */
} word;
static int *total_amount_of_words;
int countWords(FILE *file){
int count = 0;
char character;
while((character = fgetc(file)) != EOF){
if(character == '\n' || character == ' ')
count++;
}
return count;
}
void insert_word (word *words, int *n, char *s) {
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++;
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;
/* one more word */
(*n)++;
}
int wordcmp (word *a, word *b) {
if (a->count < b->count) return +1;
if (a->count > b->count) return -1;
return 0;
}
/* return 1 if c is alphabetic (a..z or A..Z), 0 otherwise */
int is_alpha (char c) {
if (c >= 'a' && c <= 'z' || c >= 'A' && c <= 'Z') return 1;
return 0;
}
void remove_char (char *s, int i) {
while (s[i]) {
i++;
s[i-1] = s[i];
}
s[i] = 0;
}
void remove_non_alpha (char *s) {
int i;
for (i=0; s[i]; i++) if (!is_alpha (s[i])) remove_char (s, i);
}
void make_lowercase (char *s) {
int i;
for (i=0; s[i]; i++) s[i] = tolower (s[i]);
}
int main(int argc, char *argv[])
{
word words[MAXWORDS];
char s[1000];
int i, j, n, m;
int pid;
FILE *current_file;
n = 0;
total_amount_of_words = mmap(NULL, sizeof *total_amount_of_words, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0);
//Create processes for each file on the command line
for(i = 1; i < argc; i++)
{
pid = fork();
if(pid == -1) //Error
{
exit(-1);
}
else if(pid == 0) //Children
{
current_file = fopen(argv[i], "r");
int current_word_amount = countWords(current_file);
*total_amount_of_words += current_word_amount;
printf("Child Process for File %s: number of words is: %i\n", argv[i], current_word_amount);
rewind(current_file);
/* read all the words in the file... */
while (!feof (current_file)) {
fscanf (current_file, "%s", s);
/* only insert the word if it's not punctuation */
if (is_alpha (s[0])) {
/* get rid of non-letters */
remove_non_alpha (s);
/* make all letters lowercase */
make_lowercase (s);
/* put this word in the list */
insert_word (words, &n, s);
}
}
fclose(current_file);
exit(0);
}
else //Parent
{
wait(NULL);
}
}
/* sort the list of words by descending frequency */
qsort((void *) words, n, sizeof (word),
(int (*) (const void *, const void *)) wordcmp);
/* print the words with their frequencies */
for (j=0; j<*total_amount_of_words; j++){
printf ("Word: %s\t", words[j].s);
printf ("Frequency: %%d\n", words[j].count);
}
printf("All %i files have been counted!\n Total Amount of Words: %d\n", (argc-1), *total_amount_of_words);
munmap(total_amount_of_words, sizeof *total_amount_of_words);
}
In the for loop at the bottom I cannot get it to print out each word and how many times it appeared. I cannot get anything to output, the struct need gets initialized. How do I share the struct with all processes?