Exchanging words in struct with codex C - c

Question

I am writing a program that will read in two files (hw8.data and codex.data) The hw8.data contains a poem and the codex.data contains words to replace in that poem. I have gotten the files to be loaded and saved in a linked list. I am having trouble finding matched words and replacing them. Also I am having trouble carrying over punctuation from the hw8 on to the newly replaced word for example. hw8: Hello World., codex: World sup, so new word in poem would be Hello sup.
Here is the hw8.data
Eye have a spelling chequer,
It came with my Pea Sea.
It plane lee marks four my revue,
Miss Steaks I can knot sea.
Eye strike the quays and type a whirred,
And weight four it two say,
Weather eye am write oar wrong,
It tells me straight aweigh.
Eye ran this poem threw it,
Your shore real glad two no.
Its vary polished in its weigh.
My chequer tolled me sew.
A chequer is a bless thing,
It freeze yew lodes of thyme.
It helps me right all stiles of righting,
And aides me when eye rime.
Each frays come posed up on my screen,
Eye trussed too bee a joule.
The chequer pours over every word,
Two cheque sum spelling rule.
The Codex.data (not all of it)
Eye I
eye I
chequer checker
Pea P
Sea C
plane plainly
lee skip
four for
revue review
Miss Mistakes
Steaks skip
knot not
sea see
quays keys
.
.
.
Here is my code:
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
struct node {
char * word;
struct node* next;
};
struct codex {
char *word1;
char *word2;
struct codex *next;
};
struct node *loadWords(FILE *stream);
struct codex *loadCodex(FILE *stream);
struct node *exchange(struct node *head, struct codex *headC);
int main()
{
FILE *stream = NULL;
struct node *head;
struct node *temp;
struct node *loop;
struct codex *headC;
struct codex *tempC;
struct codex *loopC;
head = loadWords(stream);
if (head == NULL) {
return 1;
}
temp = head;//print each word
while (temp != NULL) {
//printf ( "%s\n", temp->word);
temp = temp->next;
}
headC = loadCodex(stream);
if (headC == NULL) {
return 1;
}
tempC = headC;//print each word
while (tempC != NULL) {
//printf ( "%s %s\n", tempC->word1, tempC->word2);
tempC = tempC->next;
}
struct node *exchangedHead;
struct node *temp2;
exchangedHead = exchange(head, headC);
if (exchangedHead == NULL) {
return 1;
}
temp2 = exchangedHead;//print each word
while (temp2 != NULL) {
//printf ( "%s ", temp2->word);
temp2 = temp2->next;
}
temp = head;// free memory
while(temp != NULL) {
loop = temp->next;
free ( temp->word);
free ( temp);
temp = loop;
}
tempC = headC;// free memory
while (tempC != NULL) {
loopC = tempC->next;
free ( tempC->word1);
free ( tempC->word2);
free ( tempC);
tempC = loopC;
}
return 0;
}
/*
* This function will go through and load the words from the text file and save it to
* the struct and link the current struct to the next one
*/
struct node *loadWords(FILE *stream) {
struct node *loop = NULL;
struct node *temp = NULL;
struct node *head = NULL;
char *words = NULL;
char *currentWord;
size_t chrCount = 0;
if ((stream = fopen("hw8.data", "r")) == NULL) {
printf ("could not open file\n");
return NULL;
}
while(getline( &words, &chrCount, stream) > 0) {//read a line from file
currentWord = strtok(words, " ");//get first token
while (currentWord != NULL) {//loop through tokens
if((temp = calloc(1, sizeof(struct node))) == NULL) {
printf("ERROR - Could not allocate memory.\n");
exit(0);
}
temp->word = strdup ( currentWord);//allocate memory and copy token to word
if ( head == NULL) {
head = temp;//first structure
}
else {
loop = head;
while ( loop->next != NULL) {//loop to last structure
loop = loop->next;//add structure to end
}
loop->next = temp;
}
currentWord = strtok(NULL, " ");//next token
}
free (words);//release memory
chrCount = 0;//so readline will allocate memory for next line
words = NULL;
}
return head;
}
/*
* This function will go through and load the words from the text file and save it to
* the struct and link the current struct to the next one
*/
struct codex *loadCodex(FILE *stream) {
struct codex *loop = NULL;
struct codex *temp = NULL;
struct codex *head = NULL;
char *words = NULL;
char *currentWord;
char *currentWord2;
size_t chrCount = 0;
if (( stream = fopen("codex.data", "r")) == NULL) {
printf ("could not open file\n");
return NULL;
}
while(getline( &words, &chrCount, stream) > 0) {//read a line from file
currentWord = strtok(words, " ");//get first token
currentWord2 = strtok(NULL, "\n");
while (currentWord != NULL && currentWord2 != NULL) {//loop through tokens
if((temp = calloc(1, sizeof(struct node))) == NULL) {
printf("ERROR - Could not allocate memory.\n");
exit(0);
}
temp->word1 = strdup ( currentWord);//allocate memory and copy token to word
temp->word2 = strdup ( currentWord2);
if (head == NULL) {
head = temp;//first structure
}
else {
loop = head;
while ( loop->next != NULL) {//loop to last structure
loop = loop->next;//add structure to end
}
loop->next = temp;
}
currentWord = strtok(NULL, " ");//next token
}
free (words);//release memory
chrCount = 0;//so readline will allocate memory for next line
words = NULL;
}
return head;
}
struct node *exchange(struct node *head, struct codex *headC) {
struct node *temp;
temp = head;
while(head != NULL && headC != NULL) {
if(strcmp(head->word, headC->word1)) {
head->word = relloc(head->word, strlen(headC->word2));
head->word = headC->word2;
head->next = temp->next;
headC = headC->next;
temp = temp->next;
}
}
}

Answer 1

The issue you are having in exchange (other than misspelling realloc and failing to return a value) is failing to allocate space for the null-terminating character on realloc. (note I haven't checked the list operations for correctness)
head->word = realloc(head->word, strlen(headC->word2));
should be
head->word = realloc(head->word, strlen(headC->word2) + 1);
Which would explain why you are losing the 1-char punctuation off the end of each line.
You should also realloc to a tmp pointer and only assign head->word = tmp; if the reallocation succeeded. (otherwise you lose the original contents of head->word) Also, if you are not going to return a value from exchange, just make the function void (otherwise return head). Let me know if this doesn't correct the issue and I'll dig deeper.
More Issues
Looking at the code, I saw several more issues (some significant). Primarily, your exchange function was a train wreck. Generally, when iterating a linked list, you create a temporary pointer to iterate, rather than using the list address (as you did in main). Why didn't you do that in exchange? Given that, I scrapped exchange and rewrote it. It is included below. In your read functions, wise choice in use of getline, but there is no need to reset chrCount = 0; or words = NULL; in order for getline to allocate the next line. It does it automatically.
However, you committed a foul when you sent the line words to strtok -- without first making a copy. Why? getline allocated the space and needs to manage/free the block of memory it allocated. When you send words to strtok it modifies the memory, inserting null-terminating characters which can lead to stray errors when getline attempts to free/realloc the block. Always make a copy of the line allocated by getline before sending the line to strtok. Additionally, since you must free the copy, create a pointer to your copy so you preserve the start address for your memory block in order to pass to free when you are done.
There is no need to pass an unopened FILE* pointer to your read functions. That can be declared within the function. What you do need to pass is a filename so your read functions to know what to open. I changed main to include its arguments so you now pass the words/codex filenames as arguments.
Note: I just used your sample codex values for my test.
Look over the code at the modifications and the comments:
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
struct node {
char * word;
struct node* next;
};
struct codex {
char *word1;
char *word2;
struct codex *next;
};
struct node *loadWords(char *filename);
struct codex *loadCodex(char *filename);
struct node *exchange(struct node *head, struct codex *headC);
int main (int argc, char **argv)
{
if (argc < 3) {
fprintf (stderr, "error: insufficient input. Usage: %s nodefile codexfile\n", argv[0]);
return 1;
}
// FILE *stream = NULL;
struct node *head;
struct node *temp;
struct node *loop;
struct codex *headC;
struct codex *tempC;
struct codex *loopC;
head = loadWords(argv[1]);
if (head == NULL) {
return 1;
}
printf ("\nOriginal:\n\n");
temp = head;//print each word
while (temp != NULL) {
printf ( " %s", temp->word);
temp = temp->next;
}
printf ("\n");
headC = loadCodex(argv[2]);
if (headC == NULL) {
return 1;
}
tempC = headC;//print each word
while (tempC != NULL) {
// printf ( "%s %s\n", tempC->word1, tempC->word2);
tempC = tempC->next;
}
struct node *exchangedHead;
struct node *temp2;
exchangedHead = exchange(head, headC);
if (exchangedHead == NULL) {
return 1;
}
printf ("\nExchanged:\n\n");
temp2 = exchangedHead;//print each word
while (temp2 != NULL) {
printf ( " %s", temp2->word);
temp2 = temp2->next;
}
printf ("\n");
temp = head;// free memory
while(temp != NULL) {
loop = temp->next;
free ( temp->word);
free ( temp);
temp = loop;
}
tempC = headC;// free memory
while (tempC != NULL) {
loopC = tempC->next;
free ( tempC->word1);
free ( tempC->word2);
free ( tempC);
tempC = loopC;
}
return 0;
}
/*
* This function will go through and load the words from the text file and save it to
* the struct and link the current struct to the next one
*/
struct node *loadWords(char *filename) {
FILE *stream = NULL;
struct node *loop = NULL;
struct node *temp = NULL;
struct node *head = NULL;
char *words = NULL;
char *currentWord;
size_t chrCount = 0;
ssize_t nchr = 0;
if ((stream = fopen(filename, "r")) == NULL) {
printf ("could not open file\n");
return NULL;
}
while((nchr = getline (&words, &chrCount, stream)) != -1) {//read a line from file
char *wtemp = strdup (words); /* copy words, strtok will modify */
char *sp = wtemp; /* save wtemp address, pass sp */
currentWord = strtok(sp, " ");//get first token
while (currentWord != NULL) {//loop through tokens
if((temp = calloc(1, sizeof(struct node))) == NULL) {
printf("ERROR - Could not allocate memory.\n");
exit(0);
}
temp->word = strdup (currentWord);//allocate memory and copy token to word
if ( head == NULL) {
head = temp;//first structure
}
else {
loop = head;
while ( loop->next != NULL) {//loop to last structure
loop = loop->next;//add structure to end
}
loop->next = temp;
}
currentWord = strtok(NULL, " ");//next token
}
if (wtemp) free (wtemp);
wtemp = NULL;
// chrCount = 0; //so readline will allocate memory for next line (***NOT REQUIED***)
// words = NULL; (***NOT REQUIED***)
}
if (words) free (words);//release memory
if (stream) fclose (stream);
return head;
}
/*
* This function will go through and load the words from the text file and save it to
* the struct and link the current struct to the next one
*/
struct codex *loadCodex(char *filename) {
FILE *stream = NULL;
struct codex *loop = NULL;
struct codex *temp = NULL;
struct codex *head = NULL;
char *words = NULL;
char *currentWord;
char *currentWord2;
size_t chrCount = 0;
ssize_t nchr = 0;
if (( stream = fopen(filename, "r")) == NULL) {
printf ("could not open file\n");
return NULL;
}
while(getline( &words, &chrCount, stream) > 0) {//read a line from file
while (nchr > 0 && (words[nchr-1] == '\n' || words[nchr-1] == '\r'))
words[--nchr] = 0; /* strip newline or carriage rtn */
char *wtemp = strdup (words); /* copy words, strtok will modify */
char *sp = wtemp; /* save wtemp address, pass sp */
currentWord = strtok(sp, " ");//get first token
currentWord2 = strtok(NULL, "\n");
while (currentWord != NULL && currentWord2 != NULL) {//loop through tokens
if((temp = calloc(1, sizeof(struct node))) == NULL) {
printf("ERROR - Could not allocate memory.\n");
exit(0);
}
temp->word1 = strdup ( currentWord);//allocate memory and copy token to word
temp->word2 = strdup ( currentWord2);
if (head == NULL) {
head = temp;//first structure
}
else {
loop = head;
while ( loop->next != NULL) {//loop to last structure
loop = loop->next;//add structure to end
}
loop->next = temp;
}
currentWord = strtok(NULL, " ");//next token
}
if (wtemp) free (wtemp);
wtemp = NULL;
// chrCount = 0;//so readline will allocate memory for next line
// words = NULL;
}
if (words) free (words);//release memory
if (stream) fclose (stream);
return head;
}
// struct node *exchange(struct node *head, struct codex *headC) {
// struct node *temp;
// temp = head;
// while(head != NULL && headC != NULL) {
// if(strcmp(head->word, headC->word1)) {
// head->word = realloc(head->word, strlen(headC->word2));
// head->word = headC->word2;
// head->next = temp->next;
// headC = headC->next;
// temp = temp->next;
// }
// }
// }
struct node *exchange(struct node *head, struct codex *headC)
{
struct node *temp = head;
while(temp != NULL)
{
char *wtemp = NULL;
struct codex *tempC = headC;
while (tempC != NULL)
{
if (strcmp(temp->word, tempC->word1) == 0) {
size_t tclen = strlen(tempC->word2);
wtemp = realloc(temp->word, tclen + 1); /* add 1 for null-term */
if (!wtemp) {
fprintf (stderr, "%s() error: realloc failed.\n", __func__);
return head;
}
temp->word = wtemp;
memcpy (temp->word, tempC->word2, tclen + 1); /* copies the null-term also */
}
tempC = tempC->next;
}
temp = temp->next;
}
return head;
}
Output
$ ./bin/ll_single_replace_w dat/ll_replace_poem.txt dat/ll_replace_codex.txt
Original:
Eye have a spelling chequer,
It came with my Pea Sea.
It plane lee marks four my revue,
Miss Steaks I can knot sea.
Eye strike the quays and type a whirred,
And weight four it two say,
Weather eye am write oar wrong,
It tells me straight aweigh.
Eye ran this poem threw it,
Your shore real glad two no.
Its vary polished in its weigh.
My chequer tolled me sew.
A chequer is a bless thing,
It freeze yew lodes of thyme.
It helps me right all stiles of righting,
And aides me when eye rime.
Each frays come posed up on my screen,
Eye trussed too bee a joule.
The chequer pours over every word,
Two cheque sum spelling rule.
Exchanged:
I have a spelling chequer,
It came with my P Sea.
It plainly skip marks for my revue,
Mistakes skip I can not sea.
I strike the keys and type a whirred,
And weight for it two say,
Weather I am write oar wrong,
It tells me straight aweigh.
I ran this poem threw it,
Your shore real glad two no.
Its vary polished in its weigh.
My checker tolled me sew.
A checker is a bless thing,
It freeze yew lodes of thyme.
It helps me right all stiles of righting,
And aides me when I rime.
Each frays come posed up on my screen,
I trussed too bee a joule.
The checker pours over every word,
Two cheque sum spelling rule.