What is causing this?

[caduardo21]

I wrote this program to read two files, separate the lines read into words and write the words, the number of times they were found on both files and the number of the where they came from. For some reason, my program is skipping the last word. Can someone help me find the problem? Thanks.

text1.txt

look at the stars

text2.txt

look how they shine for you

out.txt

look 	 2 	 1
at 	 1 	 1
the 	 1 	 1
stars 	 1 	 1
how 	 1 	 2
they 	 1 	 2
shine 	 1 	 2
for 	 1 	 2

Here's the program

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define FILES 2

int add_word(const char *, const int);
int word_exists(const char *);
void write_list(void);

struct Word {
	char word[30];
	int occurrences;
	int document;
};

struct Node {
	struct Word word;
	struct Node *next;
};

struct Node *first_node = NULL;

int main(void)
{
	int i;
	FILE *in;
	char line[BUFSIZ];
	char *word = NULL;
	char list[FILES][11] = {"text1.txt", "text2.txt"};

	for(i = 0; i < FILES; ++i) {
		in = fopen(list[i], "r");
		if(in == NULL){
			printf("unknown file: %s\n", list[i]);
			return 0;
		}

		while(fgets(line, sizeof(line), in) != NULL) {
			if(strchr(line, '\n') != NULL)
				line[strlen(line) - 1] = '\0';

			word = strtok(line, " ");
			while(word != NULL) {
				add_word(word, i + 1); /* i + 1 is the document's number */
				word = strtok(NULL, " ");
			}
		}

		fclose(in);
	}

	write_list();

	return 0;
}

int add_word(const char *word2_add, const int doc_number)
{
	struct Node *new_node;
	struct Node *walker;

	if(word_exists(word2_add) == 1)
		return 0;

	else {
		new_node = (struct Node *)malloc(1 * sizeof(*new_node));

		if(new_node == NULL){
			printf("error allocating memory\n");
			exit(1);
		}

		new_node->next = NULL;
		strcpy(new_node->word.word, word2_add);
		new_node->word.occurrences = 0;
		new_node->word.occurrences++;
		new_node->word.document = doc_number;

		if(first_node == NULL)
			first_node = new_node;

		else {
			walker = first_node;

			while(walker->next != NULL)
				walker = walker->next;
			
			walker->next = new_node;
		}
	}

	return 0;
}


int word_exists(const char *word)
{

	struct Node *walker;
	walker = first_node;

	if(walker == NULL)
		return 0;

	else {
		while(walker->next != NULL) {
			if(strcmp(word, walker->word.word) == 0) {
				walker->word.occurrences++;
				return 1;
			}

			else
				walker = walker->next;
		}
	}
	
	return 0;
}

void write_list(void)
{
	FILE *out;
	struct Node *walker;
	
	walker = first_node;
	out = fopen("out.txt", "w");

	if(out == NULL) {
		printf("could not create out.txt\n");
		getchar();
		exit(1);
	}

	while(walker->next != NULL) {
		fprintf(out, "%s \t %d \t %d\n", walker->word.word, 
			    walker->word.occurrences, walker->word.document);
		walker = walker->next;
	}

	fclose(out);
}

Thanks a lot.

[Dave_Sinkula]

It's being added to the list, but it's not being printed. You could twiddle the loop like this:

   for ( ;; )
   {
      fprintf(out, "%s \t %d \t %d\n", walker->word.word,
              walker->word.occurrences, walker->word.document);
      if ( walker->next == NULL )
      {
         break;
      }
      walker = walker->next;
   }

This prints the last one, then checks for NULL.

I'd recommend looking into it more than I did for a better solution than this, but that may be the spot to start looking.

[itsme86]

	while(walker->next != NULL) {

Try changing that to:

	while(walker != NULL) {

[caduardo21]

Nice. Thanks