Circular Linked List(+ division)

// HEADER_FILE

#ifndef __C_LINKED_LIST_H__
#define __C_LINKED_LIST_H__

#define TRUE	1
#define FALSE	0

typedef int Data;

typedef struct _node
{
	Data data;
	struct _node * next;
} Node;

typedef struct _CLL
{
	Node * tail;
	Node * cur;
	Node * before;
	int numOfData;
} CList;


typedef CList List;

void ListInit(List * plist);
void LInsert(List * plist, Data data);
void LInsertFront(List * plist, Data data);

int LFirst(List * plist, Data * pdata);
int LNext(List * plist, Data * pdata);
Data LRemove(List * plist);
int LCount(List * plist);

#endif

// SOURCE_FILE

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

void ListInit(List * plist)
{
	plist->tail = NULL;
	plist->cur = NULL;
	plist->before = NULL;
	plist->numOfData = 0;
}

void LInsertFront(List * plist, Data data)
{
	Node * newNode = (Node*)malloc(sizeof(Node));
	newNode->data = data;

	if(plist->tail == NULL) 
	{
		plist->tail = newNode;
		newNode->next = newNode;
	}
	else
	{
		newNode->next = plist->tail->next;
		plist->tail->next = newNode;
	}

	(plist->numOfData)++;
}

void LInsert(List * plist, Data data)
{
	Node * newNode = (Node*)malloc(sizeof(Node));
	newNode->data = data;

	if(plist->tail == NULL) 
	{
		plist->tail = newNode;
		newNode->next = newNode;
	}
	else 
	{
		newNode->next = plist->tail->next;
		plist->tail->next = newNode;
		plist->tail = newNode;
	}

	(plist->numOfData)++;
}

int LFirst(List * plist, Data * pdata)
{
	if(plist->tail == NULL)    // 저장된 노드가 없다면
		return FALSE;

	plist->before = plist->tail;
	plist->cur = plist->tail->next;

	*pdata = plist->cur->data;
	return TRUE;
}

int LNext(List * plist, Data * pdata)
{
	if(plist->tail == NULL)    // 저장된 노드가 없다면
		return FALSE;

	plist->before = plist->cur;
	plist->cur = plist->cur->next;

	*pdata = plist->cur->data;
	return TRUE;
}

Data LRemove(List * plist)
{
	Node * rpos = plist->cur;
	Data rdata = rpos->data;

	if(rpos == plist->tail)    // 삭제 대상을 tail이 가리킨다면
	{
		if(plist->tail == plist->tail->next)    // 그리고 마지막 남은 노드라면
			plist->tail = NULL;
		else
			plist->tail = plist->before;
	}

	plist->before->next = plist->cur->next;
	plist->cur = plist->before;

	free(rpos);
	(plist->numOfData)--;
	return rdata;
}

int LCount(List * plist)
{
	return plist->numOfData;
}

// MAIN_FILE

#include <stdio.h>
#include "CLinkedList.h"

int main(void)
{
	// 원형 연결 리스트의 생성 및 초기화 ///////
	List list;
	int data, i, nodeNum;
	ListInit(&list);

	// 리스트에 5개의 데이터를 저장 /////// 
	LInsert(&list, 3);
	LInsert(&list, 4);
	LInsert(&list, 5);
	LInsertFront(&list, 2);
	LInsertFront(&list, 1);
	
	// 리스트에 저장된 데이터를 연속 3회 출력 ///////
	if(LFirst(&list, &data))
	{
		printf("%d ", data);
		
		for(i=0; i<LCount(&list)*3-1; i++)
		{
			if(LNext(&list, &data))
				printf("%d ", data);
		}
	}
	printf("\n");

	// 2의 배수를 찾아서 모두 삭제 ///////
	nodeNum = LCount(&list);

	if(nodeNum != 0)
	{
		LFirst(&list, &data);
		if(data%2 == 0)
			LRemove(&list);
		
		for(i=0; i < nodeNum-1; i++)
		{
			LNext(&list, &data);
			if(data%2 == 0)
				LRemove(&list);
		}
	}

	// 전체 데이터 1회 출력 ///////
	if(LFirst(&list, &data))
	{
		printf("%d ", data);
		
		for(i=0; i<LCount(&list)-1; i++)
		{
			if(LNext(&list, &data))
				printf("%d ", data);
		}
	}
	return 0;
}