[C] Doubly linked list (full source)

phyrrus9 · 12-18-2014, 02:14 PM

There will be no tutorial here.. If you want me to break it all down, I can, but this is just for people to use:

DoublyLinkedList.h

Code:
#ifndef DLLTYPE_H
#define DLLTYPE_H

/*this lets us easily change our types*/
#define DLLDT int

struct DLLNode
{
	DLLDT data;
	struct DLLNode *p, *n; //parent and next
};

struct DLLType
{
	struct DLLNode *head;
	struct DLLNode *tail;
};

typedef struct DLLType DLLType;

void  DLLInit(DLLType list);
void  DLLInsert(DLLType list, DLLDT obj);
DLLDT DLLGet(DLLType list, int index);
void  DLLRemove(DLLType list, int index);
int   DLLCount(DLLType list);
void  DLLFree(DLLType list);

struct DLLNode *DLLGetObj(DLLType list, int index);

#endif

DoublyLinkedList.c

Code:
#include "DoublyLinkedList.h"
#include <stdlib.h>

void DLLInit(DLLType list)
{ list.head = list.tail = NULL; }

void DLLInsert(DLLType list, DLLDT obj)
{
	struct DLLNode *inNode = malloc(sizeof(struct DLLNode));
	inNode->data = obj;
	inNode->n = NULL;
	if (list.head == NULL)
	{
		inNode->p = NULL;
		list.head = list.tail = inNode;
	}
	else
	{
		inNode->p = list.tail;
		list.tail->n = inNode;
		list.tail = inNode;
	}
}

DLLDT DLLGet(DLLType list, int index)
{
	struct DLLNode *c = list.head;
	int i;
	for (i = 0; i < index; i++, c = c->n);
	return c->data;
}

struct DLLNode * DLLGetObj(DLLType list, int index)
{
	struct DLLNode *c = list.head;
	int i;
	for (i = 0; i < index; i++, c = c->n);
	return c;
}


void DLLRemove(DLLType list, int index)
{
	struct DLLNode *c = DLLGetObj(list, index);
	c->p->n = c->n;
	c->n->p = c->p;
	free(c);
}

int DLLCount(DLLType list)
{
	struct DLLNode *c = list.head;
	int i;
	for (i = 0; c != NULL; i++, c = c->n);
	return i;
}

void DLLFree(DLLType list)
{
	struct DLLNode *c = list.head, *c2;
	while (c)
	{
		c2 = c->n;
		free(c);
		c = c2;
	}
}

You don't have to use the wrapper functions if you don't want. It just lets you traverse the list more freely (if done manually)