Question

Ok, so I’m almost finished with this program for my final project and I am receiving a segmentation fault… The program will do everything correctly, and it will print to the screen everything however it does not get out of the printWordLength() function. prints segmentation fault right at the end, I’m certain this is a simple fix but my brain is crashing at this moment in time. (Scroll down to very bottom for the culprit print function.

If you just want to use my code, feel free.

Purpose: This program holds a doubly linked list that will read a file that is entered as a command line argument, read each line from file, tokenize each word from line and for each word will place it into a Word Length structure depending on its length and then will place it into a word_count structure dependent on the word’s string and count each word’s occurrence in a file.

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

#define DELIM " ,.+-=!?:;\t"
#define MAXLINE 25000

typedef struct word_count
{
    char * word;
    int count;
    struct word_count *next;
    struct word_count *prev;
} WORD;

typedef struct word_length_count
{
    int length;
    int count;
    WORD * words;
    struct word_length_count *next;
    struct word_length_count *prev;
} WLENGTH;

int splitIntoWords(char line[]);
void processLength(char * word);
void processWord(char * word, WORD * wordCount);
void printWordLength();
WLENGTH * createWordLength(char *word);
WORD * createWordCount(char *word);

WLENGTH * wordLength = NULL;

int main(unsigned int argc, unsigned char *argv[]){
    FILE *fpin;
    char line[MAXLINE];
    int totalWordCount = 0;

    if((fpin = fopen(argv[1], "r")) == NULL)
    {
            printf("Can't open input file.\n");
            exit(-1);
    }

    printf("This is the words all tokenized from the input!\n");
    while(fgets(line, MAXLINE, fpin) != NULL)
    {
            line[strcspn(line, "\n")] = '\0';
            if(line[0] == '\0')
                    continue;
            totalWordCount += splitIntoWords(line);
    }
    printf("Total number of words is: %d\n", totalWordCount);
    printWordLength();
    printf("\nFINISHED!");
}

int splitIntoWords(char line[])
{
    char *word;
    int count=0;
    word = strtok(line, DELIM);
    for(;word != NULL;)
    {
            count++;
            printf("%s\n", word);
            processLength(word);
            word = strtok(NULL, DELIM);
    }
    return count;
}

void processLength(char * word)
{
    WLENGTH *wLCounter = NULL;
    WLENGTH *wLLast = NULL;

    if(wordLength == NULL)
    {
            wordLength = createWordLength(word);
            return;
    }

    wLCounter = wordLength;

    while(wLCounter != NULL)
    {
            if(strlen(word) == wLCounter->length)
            {
                    ++wLCounter->count;
                    processWord(word, wLCounter->words);
                    return;
            }
            wLLast = wLCounter;
            wLCounter = wLCounter->next;
    }
    wLLast->next = createWordLength(word);
}

void processWord(char * word, WORD * wordCount){
    WORD * wCounter = NULL;
    WORD * wLast = NULL;

    if(wordCount == NULL)
    {
            wordCount = createWordCount(word);
            return;
    }
    wCounter = wordCount;
    while(wCounter != NULL)
    {
            if(strcmp(word, wCounter->word) == 0)
            {
                    ++wCounter->count;
                    return;
            }
            wLast = wCounter;
            wCounter = wCounter->next;
    }
    wLast->next = createWordCount(word);
}

WLENGTH * createWordLength(char *word)
{
    WLENGTH *wLCounter = NULL;
    wLCounter = (WLENGTH*)malloc(sizeof(WLENGTH));
    //wLCounter->count = (int*)malloc(int));
    //wLCounter->length = (int*)malloc(int));
    wLCounter->words = createWordCount(word);
    wLCounter->count = 1;
    wLCounter->length = strlen(word);
    wLCounter->next = NULL;
    return wLCounter;
}

WORD * createWordCount(char *word)
{
    WORD *wCount = NULL;
    wCount = (WORD*)malloc(sizeof(WORD));
    wCount->word = (char*)malloc(strlen(word+1));
    strcpy(wCount->word, word);
    wCount->count = 1;
    wCount->next = NULL;
    return wCount;
}

void printWordLength(){
    WLENGTH * temp = wordLength;
    WORD * tempWORD = wordLength->words;
    while(temp != NULL)
    {
            tempWORD = temp->words;
            printf("\nFor Word Length: %d : There are: %d occurances!\n",  temp->length, temp->count);
            while(tempWORD != NULL)
            {
                    printf("\t%s\toccurs:%d\n", tempWORD->word, tempWORD->count);
                    tempWORD = tempWORD->next;
            }
            temp = temp->next;
    }
}

I received no segmentation fault until I added the while loop for tempWORD. But the brain fart moment I am having is I don’t know the issue. Maybe pointer problem?

Answer 1

Without having made an effort to understand the code, the very last line looks like a problem – you need to check temp != NULL before assigning tempWORD = temp->words. Unless you intended to do the tempWord = temp->words assignment before moving to temp->next