linkedlists.c

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

struct LinkedList {
	int					number;
	struct LinkedList	*next;
};

typedef struct LinkedList llist;

void	PrintLinkedList( llist* );
llist*	ReverseLinkedList( llist* );
llist*	CreateLinkedList( void );

int main (int argc, const char * argv[]) {
	llist	*head;
	
	printf("\nLet's count down!\n-------------\n");
	
	head = CreateLinkedList();
	PrintLinkedList(head);
	
	printf("\nNow try going up!\n-------------\n");
	
	head = ReverseLinkedList(head);
	PrintLinkedList(head);
		
	return 0;
}

void	PrintLinkedList( llist *head ) {
	llist	*curPtr;
	
	curPtr = head;
	
	while (curPtr != NULL) {
		printf("Number: %d\n", curPtr->number);
		curPtr = curPtr->next;
	}
}

llist*	CreateLinkedList( void ) {
	llist	*curr, *head;
	int		num;
	
	head = NULL;
	
	for (num=1; num <= 12; num++) {
		curr = (llist *)malloc( sizeof(llist) );
		
		curr->number = num;
		curr->next = head;
		
		head = curr;
	}
		
	return curr;
}

llist* ReverseLinkedList( llist *head ) {
	llist	*temp, *next_ptr, *prev_ptr;
	
	next_ptr = head;
	prev_ptr = NULL;
	
	while (next_ptr != NULL) {
		temp = next_ptr;
		next_ptr = temp->next;
		temp->next = prev_ptr;
		prev_ptr = temp;
	}
	
	head = temp;
	
	return head;
}