Thread: Can anybody see what's wrong with this code? it's supposed to sort a linked list alph

I've been wrestling with this for some hours and I'm wondering if anyone can see what's wrong with it.

Here is my full compileable, formatted code code: http://dustinnerayis.boldlygoingnowh...signment%204.c



Thanks a lot in advance!


Here are the necessary parts:

Code:

int main(void) {
	srand ( time(NULL) );
	BOOK books;				// Both of these should be stored as pointers and malloc should be used to make things easier for myself but when I switch it and make the necessary changes, the program still crashes
	MEMBER club;
	club.next = NULL;
	books.ISBN[0] = 'a';
	books.next = &books;
..........

Code:

	else if (userInput == 2) {	// let's sort the books by title!
				//books = *bookSortByTitle(&books);
				BOOK* newStart = bookSortByTitle(&books);			
				BOOK* currentBook = newStart->next;
				//while (currentBook->next != newStart) {
				//	currentBook = currentBook->next;
			//	}
				currentBook->next = &books;
				books = *newStart;
				printf("\nI sorted your books alphabetically by title\n");
			}

Code:

BOOK * bubbleSortBookTitle(BOOK * head, int count)
{
	BOOK *parent, *newhead, *temp;
	int again = 1;

	newhead = head;
	while(again)
	{
		head = newhead; /* set head to the first element in the list */
		parent = NULL; /* current head is first element, it has no parent */
		again = 0; /* should we sort again? only if a swap is made */
		int i;
		for(i=0; i<count-1; i++)
		{
			if( compareBooks(head, head->next) == -1 )
			{
				/* if head->next should come before head then swap them */
				temp = head->next;
				head->next = head->next->next;
				temp->next = head;
				head = temp;
				if(parent != NULL) /* if this is not the first element in the list */
					parent->next = head;

				else /* if there is no parent to this head, that means this is the
					    beginning of the list so we'll set the newhead to this */
					newhead = head;

				again = 1; /* we made a swap so we'll have to go through the while loop again */
			}

			parent = head;
			head = head->next;
		}
	}

	return newhead;
}

Code:

int compareBooks(BOOK * first, BOOK * second)
{
return compareStrings(first->title, second->title);
}

Code:

BOOK* bookSortByTitle(BOOK* firstBook) {
	int elements = 1;
	BOOK* testBook = firstBook->next;
	while (testBook != firstBook) {
		testBook = testBook->next;
		elements++; }
	return bubbleSortBookTitle(firstBook, elements);
}

Code:

int compareStrings(char * first, char * second)
{
/* reached end of strings, they are equal */
if(first[0] == '\0' && second[0] == '\0') return 0;

/* if first characters are equal(non case sensitive) do a recursive call starting at the second character of each string */
if ( toupper(first[0]) == toupper(second[0]) ) return compareStrings(first + 1, second + 1);

/* return 1 if first comes before second, return -1 if second comes before first */
if ( toupper(first[0]) < toupper(second[0]) ) return 1;
else return -1;
}

strcmp treats capitals and lowercase differently thats why I have a different one