实现双向循环链表 - 详解

双向循环链表

本文章将展示zack实现双向循环链表的代码

// list.h
#pragma once
#include<stdio.h>#include<stdlib.h>#include<assert.h>#include<stdbool.h>typedef int data_type;typedef struct list_node{data_type data;struct list_node* next;struct list_node* prve;}list_node;list_node* buy_node(data_type x);void list_init(list_node** pphead);void list_print(list_node* phead);void list_push_back(list_node* phead, data_type x);void list_push_front(list_node* phead, data_type x);bool list_empty(list_node* phead);void list_pop_back(list_node* phead);void list_pop_front(list_node* phead);list_node* list_find(list_node* phead, data_type x);// 在指定位置之前插入void list_insert(list_node* pos, data_type x);void list_erase(list_node* pos);void list_destroy(list_node** pphead);

// list.c
#define _CRT_SECURE_NO_WARNINGS 1
#include"list.h"
list_node* buy_node(data_type x)
{
list_node* new_node = (list_node*)malloc(sizeof(list_node));
if (new_node == NULL)
{
perror("malloc fail");
exit(1);
}
new_node->data = x;
new_node->next = new_node->prve = new_node;
return new_node;
}
void list_init(list_node** pphead)
{
*pphead = buy_node(-1);
}
void list_print(list_node* phead)
{
list_node* pcur = phead->next;
while (pcur != phead)
{
printf("%d->", pcur->data);
pcur = pcur->next;
}
printf("\n");
}
void list_push_back(list_node* phead, data_type x)
{
assert(phead);
list_node* new_node = buy_node(x);
new_node->next = phead;
new_node->prve = phead->prve;
phead->prve->next = new_node;
phead->prve = new_node;
}
void list_push_front(list_node* phead, data_type x)
{
assert(phead);
list_node* new_node = buy_node(x);
new_node->next = phead->next;
new_node->prve = phead;
phead->next->prve = new_node;
phead->next = new_node;
}
bool list_empty(list_node* phead)
{
assert(phead);
return phead->next == phead;
}
void list_pop_back(list_node* phead)
{
list_empty(phead);
assert(phead);
list_node* del = phead->prve;
phead->prve->prve->next = phead;
phead->prve = phead->prve->prve;
free(del);
del = NULL;
}
void list_pop_front(list_node* phead)
{
list_empty(phead);
assert(phead);
list_node* del = phead->next;
phead->next->next->prve = phead;
phead->next = phead->next->next;
free(del);
del = NULL;
}
list_node* list_find(list_node* phead, data_type x)
{
list_node* pcur = phead->next;
while (pcur != phead)
{
if (pcur->data == x)
return pcur;
pcur = pcur->next;
}
return NULL;
}
void list_insert(list_node* pos, data_type x)
{
assert(pos);
list_node* new_node = buy_node(x);
new_node->next = pos;
new_node->prve = pos->prve;
pos->prve->next= new_node;
pos->prve = new_node;
}
void list_erase(list_node* pos)
{
assert(pos);
pos->prve->next = pos->next;
pos->next->prve = pos->prve;
free(pos);
pos = NULL;
}
void list_destroy(list_node** pphead)
{
assert(pphead &&
*pphead);
list_node* pcur = (*pphead)->next;
while (pcur != *pphead)
{
list_node* del = pcur;
pcur = pcur->next;
free(del);
del = NULL;
}
free(*pphead);
*pphead = NULL;
pcur = NULL;
}

// test.c
#define _CRT_SECURE_NO_WARNINGS 1
#include"list.h"
void list_test01()
{
list_node* plist;
list_init(&plist);
// 这里是传哨兵位的地址，因为plist的指向发生改变
list_push_back(plist, 1);
list_push_back(plist, 2);
list_push_back(plist, 3);
list_push_back(plist, 4);
list_push_back(plist, 5);
list_print(plist);
list_push_front(plist, 5);
list_push_front(plist, 4);
list_push_front(plist, 3);
list_push_front(plist, 2);
list_print(plist);
}
void list_test02()
{
list_node* plist;
list_init(&plist);
list_push_back(plist, 1);
list_push_back(plist, 2);
list_push_back(plist, 3);
list_push_back(plist, 4);
list_print(plist);
list_pop_back(plist);
list_print(plist);
list_pop_back(plist);
list_print(plist);
list_pop_back(plist);
list_print(plist);
list_pop_back(plist);
list_print(plist);
}
void list_test03()
{
list_node* plist;
list_init(&plist);
list_push_back(plist, 1);
list_push_back(plist, 2);
list_push_back(plist, 3);
list_push_back(plist, 4);
list_print(plist);
list_pop_front(plist);
list_print(plist);
list_pop_front(plist);
list_print(plist);
list_pop_front(plist);
list_print(plist);
}
void list_test04()
{
list_node* plist;
list_init(&plist);
list_push_back(plist, 1);
list_push_back(plist, 2);
list_push_back(plist, 3);
list_push_back(plist, 4);
list_print(plist);
list_node* pos = list_find(plist, 1);
list_insert(pos, 22);
list_print(plist);
pos = list_find(plist, 22);
list_erase(pos);
list_print(plist);
list_destroy(&plist);
}
int main()
{
//list_test01();
//list_test02();
//list_test03();
list_test04();
return 0;
}

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