Program to print and sum numbers in a text file - c

Question

I want to write a program which print all numbers found in a file and then add them up. I have two problems:
How to add up the numbers I've printed?
Why in output_file do I have so many commas:
Here's my code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#define CHUNK 12
char *getWord(FILE *infile);
void clean(char *dirty);
char *getWord(FILE *infile)
{
char *word, *word2;
int length, cursor, c;
word = (char*)malloc(sizeof(char)*CHUNK);
if(word == NULL) return NULL;
length = CHUNK;
cursor = 0;
while(!isspace(c = getc(infile)) && !feof(infile))
{
word[cursor] = c;
cursor++;
if(cursor >= length)
{
length += CHUNK;
word2 = (char*)realloc(word, cursor);
if(word2 == NULL)
{
free(word2);
return NULL;
}
else
{
word = word2;
}
}
}
word[cursor] = '\0';
return word;
}
void clean(char *dirty)
{
int i = 0, j = 0;
char *temp;
temp = strdup(dirty);
while(i < strlen(temp))
{
if(isdigit(temp[i]))
{
dirty[j] = temp[i];
j++;
}
i++;
}
dirty[j] = '\0';
free(temp);
}
int main(int argc, char *argv[])
{
char *word;
FILE *infile, *outfile;
if(argc != 3)
{
printf("Missing argument!\n");
exit(1);
}
infile = fopen(argv[1], "r");
if(infile != NULL)
{
outfile = fopen(argv[2], "w");
if(outfile == NULL)
{
printf("Error, cannot open the outfile!\n");
abort();
}
else
{
while(!feof(infile))
{
word = getWord(infile);
if(word == NULL)
{
free(word);
abort();
}
clean(word);
fputs(word, outfile);
fputs(",", outfile);
free(word);
}
}
}
else
{
printf("Error, cannot open the outfile!\n");
abort();
}
fclose(infile);
fclose(outfile);
return 0;
}
infile:

Answer 1

You are getting , because of this -
fputs(",", outfile);

Answer 2

It is related in structure to the echo unix command. The core of the program could be simplified to something along the following lines:
int c, need_comma = 0;
while ((c = fgetc(infile)) != EOF) {
if (isdigit(c)) {
fputc(c, outfile);
need_comma = 1;
}
else {
if (need_comma == 1) {
fputc(',', outfile);
need_comma = 0;
}
}
}
this removes the need for getWord and clean functions.
This is just the printing part. the intermediate file is in CSV format,
which is structured and easy to parse and add the numbers (and print the
result to another file).