Nearly there with getting this program finished but I've run into another problem - my program keeps crashing after trying to implement a merge sort. It all compiles OK but crashes as soon as I run it.
I'm thinking the fault lies with my method of checking the words being added to the list - I'm reading in words from a text file, storing the unique ones in the list, and counting how many of them appear in the text. If I just read in every word (without counting etc), the program appears to work OK.
Anyway, here's my code - I would be extremely grateful if someone could highlight where I'm going wrong.
Code:#include <stdio.h> #include <string.h> #include <stdlib.h> #include <ctype.h> typedef struct wordList { int entries; char words[50]; struct wordList *next; } wordList_t; wordList_t *MergeSort (wordList_t *head); wordList_t *Merge (wordList_t *ptr1, wordList_t *ptr2); wordList_t *talloc (void) { return (wordList_t *)malloc(sizeof(wordList_t)); } wordList_t *AddToList (wordList_t *head, char word[]) { wordList_t *current = NULL; wordList_t *ptr = head; int found = 0; while (ptr != NULL){ if (strcmp(ptr->words, word) == 0){ ptr->entries++; found = 1; } ptr = ptr->next; } if ((head != NULL) && (found == 0)){ current = talloc(); strcpy (current->words, word); current->entries = 1; current->next = head; head = current; } if (head == NULL) { head = talloc(); head->next = NULL; strcpy (head->words, word); head->entries = 1; } return head; } wordList_t *MergeSort (wordList_t *head) { wordList_t *ptr1, *ptr2; if ((head == NULL) || (head->next == NULL)) return head; ptr1 = head; ptr2 = head->next; while ((ptr2 != NULL) && (ptr2->next != NULL)){ head = head->next; ptr2 = ptr2->next->next; } ptr2 = head->next; head->next = NULL; return Merge(MergeSort(ptr1), MergeSort(ptr2)); } wordList_t *Merge (wordList_t *ptr1, wordList_t *ptr2) { wordList_t *ptr3; if (ptr1 == NULL) return ptr2; if (ptr2 = NULL) return ptr1; if (ptr1->entries < ptr2->entries){ ptr3 = ptr1; ptr3->next = Merge(ptr1->next, ptr2); } else{ ptr3 = ptr2; ptr3->next = Merge(ptr1, ptr2->next); } return ptr3; } void PrintList (wordList_t *head) { FILE *newhtml = fopen("new.html", "w"); fprintf(newhtml,"<html><body>\n<ul>"); while (head != NULL){ fprintf(newhtml, "<li>%i - %s</li>", head->entries, head->words); head = head->next; } fprintf(newhtml,"</ul></body></html>"); fclose(newhtml); } int main (int argc, char *argv[]) { char c; int i, j = 0; char word[50]; FILE *src; wordList_t *list = NULL; if ((src = fopen (argv[1], "r")) == NULL) printf("You did not specify a document or the document cannot be found!"); else { for (i = 0; (c = fgetc(src)) != EOF; ++i){ if (isalpha(c)) word[j++] = tolower(c); else if ((!isalpha(c)) && (j != 0)){ word[j++] = '\0'; list = AddToList (list, word); j = 0; } } fclose(src); PrintList(MergeSort(list)); free(list); } return 0; }
Originally Posted by vart
