Word count problems - c

Question

I'm trying to finishing one of my C homework questions. Here's the definition and sample IO:
Description
Given an article as input. You have to count the number of each word, and prints the list of words in alphabetical order.
Sample Input
It was the best of times, it was the worst of times, it was the age of
wisdom, it was the age of foolishness, it was the epoch of belief, it
was the epoch of incredulity, it was the season of Light, it was the
season of Darkness, it was the spring of hope, it was the winter of
despair, we had everything before us, we had nothing before us, we
were all going direct to Heaven, we were all going direct the other
way.
Sample Output
age 2
all 2
before 2
belief 1
best 1
darkness 1
despair 1
direct 2
epoch 2
everything 1
foolishness 1
going 2
had 2
heaven 1
hope 1
incredulity 1
it 10
light 1
nothing 1
of 10
other 1
season 2
spring 1
the 11
times 2
to 1
us 2
was 10
way 1
we 4
were 2
winter 1
wisdom 1
worst 1
And this is my code now:
in main.c:
#include <stdio.h>
#include <stdlib.h>
#include "function.h"
#include <string.h>
int main()
{
char wordcollected [3100] = {0};
char *word_ptr[100];
int countarray[100];
static char temp[31];
int nth_word = 0;
while(1){
int n = strlen(wordcollected);
word_ptr [nth_word] = wordcollected + strlen(wordcollected);
if(strcpy(temp, fetch_word()) == NULL){
for(n == strlen(wordcollected); n >= 0; n--){
if(wordcollected[n] == ','){
wordcollected[n] = '\0';
}
}
break;
}
strcat((wordcollected), temp);
strcat((wordcollected), ",");
nth_word ++;
}
}
Our TA have already finished partial codes for us:
in function.c:
#include "function.h"
#include <stdio.h>
// fetch words from stdin
const char *fetch_word(){
static char skip_symbol[] = " \t\n,.;:?()[]{}\"\"''" ;
static char line_buffer[1024] ;
static char *now = NULL ;
// try to read a line from stdin
for( ;; ){
if( now == NULL)
now = fgets( line_buffer, sizeof(line_buffer), stdin ) ;
// End Of File?
if( now == NULL )
return NULL ;
// skip symbols
for( ; *now ; now++ ){
int size = sizeof( skip_symbol ) ;
int i ;
for( i=0 ; i<size ; i++ ){
if( *now == skip_symbol[i] )
break ;
}
// if not match skip_symbol[]
if( i >= size )
break ;
}
// End Of Line?
if( *now == '\0' ){
now = NULL ;
continue ;
}
char *word = now ;
for( ; *now ; now++ ){
int size = sizeof( skip_symbol ) ;
int i ;
for( i=0 ; i<size ; i++ ){
if( *now == skip_symbol[i] )
break ;
}
// if match skip_symbol[]
if( i < size )
break ;
}
if( *now ){
*now = '\0' ;
now ++ ;
}
return word ;
}
return NULL ;
}
In function.h:
#ifndef __FUNCTION_H__
#define __FUNCTION_H__
// fetch words from stdin
const char *fetch_word() ;
#endif
The function *fetch_word() will return a pointer points to each word in stdin while running, and will also return NULL if the function already reaches the End-Of-File. But everytime when it reach to EOF, it just keep saying segmentation fault and the system halted. How can I detect the return value of fetch_word(), know when I reached the End-Of-File, and also prevent from losing any words?

Answer 1

You need to break at the end sign before you do the cycle:
if(strcpy(temp, fetch_word()) == NULL){
break;
for(n == strlen(wordcollected); n >= 0; n--){
if(wordcollected[n] == ','){
wordcollected[n] = '\0';
}
}
}
But take my advice and refactor your code and make it more readable. You will save yourself a lot of time that way.
Also, algorithmically, for me it seems that you might want to create a linked list of words, paired with a number (implement the linked list data structure to achieve that) and whenever you read a word, try to find it in the linked list until you reach something lower than the word alphabetically or the end of the list, or a match. If you find a match, add 1 to the number. Otherwise insert the word with 1 as value at its corresponding place.

Answer 2

For fetching words, you can use following fetch_words().
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
void print_word(const char *word, void *arg)
{
printf("[Word] <%s>\n", word);
}
/*
* #fp file pointer
* #func recall function whch has two params (word, arg)
* #arg the second param of func
* */
void fetch_words(FILE *fp, void (*func)(const char *, void *), void *arg)
{
char area[256] = {0};
char buff[128];
int size = sizeof(buff) - 1;
char *delim = " \t\n,.;:?(){}\"'";
char *last;
char *token;
int len;
char *pos;
while (fgets(buff, size, fp) != NULL)
{
/* Append part of buff into area */
len = size - strlen(area);
strncat(area, buff, len);
pos = area + strlen(area);
/* Split string in area */
if ((token = strtok(area, delim)) != NULL)
{
last = token;
while ((token = strtok(NULL, delim)) != NULL)
{
func(last, arg);
last = token;
}
if (last + strlen(last) == pos)
{
/* Copy last token into area */
strcpy(area, last);
}
else
{
/* Clean area */
area[0] = 0;
func(last, arg);
last = NULL;
}
}
/* Append left part of buff into area for next loop */
if (len < strlen(buff))
{
strcat(area, buff + len);
}
}
if (last)
{
func(last, arg);
}
}
int main(int argc, char *argv)
{
fetch_words(stdin, print_word, NULL);
return 0;
}
For word counting, you can use hashmap (Key, Value). Key is word, and Value is count of word.
Here is a simple implementation of hashmap in C:
https://github.com/foreverpersist/hashmap