带头双向链表接口的实现

接口

//带头双向链表
#include <stdio.h>
#include <assert.h>
#include <malloc.h>

typedef int datatype;

typedef struct ListNode{
	datatype data;
	struct ListNode* next;
	struct ListNode* prev;
}ListNode;

typedef struct TwoList{
	struct ListNode* head;
}TwoList;

//初始化
void TwoListInit(TwoList* pt);
//销毁
void TwoListDestroy(TwoList* pt);

//尾插
void TwoListPushBack(TwoList* pt, datatype x);
//头插
void TwoListPushFront(TwoList* pt, datatype x);

//尾删
void TwoListPopback(TwoList* pt);
//头删
void TwoListPopFront(TwoList* pt);

//查找
ListNode* TwoListFind(TwoList* pt, datatype x);
//在pos 前面插入
void TwoListInsert(ListNode* pos, datatype x);
//删除pos位置的元素
void TwoListErase(ListNode* pos);
//删除x
void TwoListRemove(TwoList* pt, datatype x);

void Printf(TwoList* pt);

实现

#include "TwoList.h"

//初始化
void TwoListInit(TwoList* pt){
	assert(pt);
	pt->head = (ListNode*)malloc(sizeof(ListNode));
	pt->head->data = 0;
	pt->head->next = pt->head;
	pt->head->prev = pt->head;
}
//销毁
void TwoListDestroy(TwoList* pt){
	assert(pt);
	ListNode* head = pt->head;
	ListNode* cur = head->next;
	ListNode* next = cur->next;	
	while (cur != head){
		free(cur);
		cur = next;
		next = next->next;
	}
	free(head);
	pt->head = NULL;
}

//尾插
void TwoListPushBack(TwoList* pt, datatype x){
	assert(pt);
	ListNode* head = pt->head;
	ListNode* newNode = (ListNode*)malloc(sizeof(ListNode));
	newNode->data = x;
	head->prev->next = newNode;
	newNode->prev = head->prev;
	newNode->next = head;
	head->prev = newNode;
	
	
}
//头插
void TwoListPushFront(TwoList* pt, datatype x){
	assert(pt);
	ListNode* head = pt->head;
	ListNode* next = head->next;
	ListNode* newNode = (ListNode*)malloc(sizeof(ListNode));
	newNode->data = x;
	head->next = newNode;
	next->prev = newNode;
	newNode->next = next;
	newNode->prev = head;
	
}

//尾删
void TwoListPopback(TwoList* pt){
	assert(pt);
	//链表为空
	if (pt->head->next == pt->head){
		return;
	}
	ListNode* cur = pt->head->prev;
	ListNode* prev = cur->prev;
	free(cur);
	prev->next = pt->head;
	pt->head->prev = prev;
}
//头删
void TwoListPopFront(TwoList* pt){
	assert(pt);
	ListNode* cur = pt->head->next;
	ListNode* next = cur->next;
	free(cur);
	cur = NULL;
	pt->head->next = next;
	next->prev = pt->head;
}

//查找
ListNode* TwoListFind(TwoList* pt, datatype x){
	assert(pt);
	ListNode* cur, *next;
	if (pt->head->next == pt->head){
		return NULL;
	}
	cur = pt->head->next;
	next = cur->next;
	while (cur != pt->head){
		if (cur->data = x){
			return cur;
		}
		cur = next;
		next = next->next;
	}
	return NULL;
}
//在pos 前面插入
void TwoListInsert(ListNode* pos, datatype x){
	assert(pos);
	ListNode* prev = pos->prev;
	ListNode* newNode = (ListNode*)malloc(sizeof(ListNode));
	newNode->data = x;
	prev->next = newNode;
	pos->prev = newNode;
	newNode->prev = prev;
	newNode->next = pos;
	
}
//删除pos位置的元素
void TwoListErase(ListNode* pos){
	assert(pos);
	ListNode* prev = pos->prev;
	ListNode* next = pos->next;
	free(pos);
	pos = NULL;
	prev->next = next;
	next->prev = prev;
}
//删除x
void TwoListRemove(TwoList* pt, datatype x){
	assert(pt);
	ListNode* prev = pt->head;
	ListNode* cur = pt->head->next;
	ListNode* next = cur->next;
	while (cur != pt->head){
		if (cur->data == x){
			free(cur);
			cur = NULL;
			prev->next = next;
			next->prev = prev;
			return;
		}
		prev = cur;
		cur = next;
		next = next->next;
	}
}

void Printf(TwoList* pt){
	assert(pt);
	ListNode* head = pt->head;
	ListNode* cur = head->next;
	ListNode* next = cur->next;
	while(cur != head){
		printf("%d ", cur->data);
		cur = next;
		next = next->next;
	}
}