双向循环链表的接口设计

/********************************************************************************************************
*
*
* 设计双向循环链表的接口
*
* 
*
* Copyright (c)  2023-2024   cececlmx@126.com   All right Reserved
* ******************************************************************************************************/
#include <stdio.h>
#include <stdbool.h>
#include <stdlib.h>


//指的是双向循环链表中的结点有效数据类型，用户可以根据需要进行修改
typedef int  DataType_t;

//构造双向循环链表的结点,链表中所有结点的数据类型应该是相同的
typedef struct DoubleLinkedList
{
	DataType_t  		     data; //结点的数据域
	struct DoubleLinkedList	*prev; //直接前驱的指针域
	struct DoubleLinkedList	*next; //直接后继的指针域

}DoubleCirLList_t;


//创建一个空双向循环链表，空链表应该有一个头结点，对链表进行初始化
DoubleCirLList_t * DoubleCirLList_Create(void)
{
	//1.创建一个头结点并对头结点申请内存
	DoubleCirLList_t *Head = (DoubleCirLList_t *)calloc(1,sizeof(DoubleCirLList_t));
	if (NULL == Head)
	{
		perror("Calloc memory for Head is Failed");
		exit(-1);
	}

	//2.对头结点进行初始化，头结点是不存储数据域，指针域指向自身即可，体现"循环”
	Head->prev = Head;
	Head->next = Head;

	//3.把头结点的地址返回即可
	return Head;
}

//创建新的结点，并对新结点进行初始化（数据域 + 指针域）
DoubleCirLList_t * DoubleCirLList_NewNode(DataType_t data)
{
	//1.创建一个新结点并对新结点申请内存?
	DoubleCirLList_t *New = (DoubleCirLList_t *)calloc(1,sizeof(DoubleCirLList_t));
	if (NULL == New)
	{
		perror("Calloc memory for NewNode is Failed");
		return NULL;
	}

	//2.对新结点的数据域和指针域进行初始化,指针域指向结点自身，体现“循环“
	New->data = data;
	New->prev = New;
	New->next = New;

	return New;
}

//头插
bool DoubleCirLList_HeadInsert(DoubleCirLList_t *Head,DataType_t data)
{
	
	DoubleCirLList_t *Phead=Head->next;
	DoubleCirLList_t *New = DoubleCirLList_NewNode(data);
	if (NULL == New)
	{
		perror("Calloc memory for NewNode is Failed");
		return NULL;
	}
	
	if(Phead->next==Head)
	{
		Head->next=New;
		return true;
	}

	New->prev=Phead->prev;
	New->next=Phead;

	Phead->prev->next=New;
	Phead->prev=New;
	Head->next=New;


	return true;
}

//尾插
bool DoubleCirLList_tailInsert(DoubleCirLList_t *Head,DataType_t data)
{
	DoubleCirLList_t *Phead = Head->next;
	DoubleCirLList_t *New = DoubleCirLList_NewNode(data);
	if (NULL == New)
	{
		perror("Calloc memory for NewNode is Failed");
		return false;
	}

	if(Phead==Head)
	{
		Head->next=New;
		return true;
	}

	New->prev = Phead->prev;
	New->next = Phead;

	Phead->prev->next = New;
	Phead->prev=New;
	return true;
}

//指定位置插入
bool DoubleCirLList_DestInsert(DoubleCirLList_t *Head,DataType_t destval,DataType_t data)
{

	DoubleCirLList_t *Phead = Head->next;
	DoubleCirLList_t *New = DoubleCirLList_NewNode(data);
	if (NULL == New)
	{
		perror("Calloc memory for NewNode is Failed");
		return NULL;
	}

	if(Phead==Head)
	{
		Head->next=New;
		return true;
	}

	while(Phead->data != destval)
	{
		if(Phead->next==Head->next)
		{
			printf("dest node is not found\n");
			return false;
		}
		Phead = Phead->next;
	}
	

	New->next=Phead->next;
	New->prev=Phead;

	Phead->next->prev=New;
	Phead->next=New;


	return true;
}

//头删
bool DoubleCirLList_HeadDel(DoubleCirLList_t *Head)
{
	//对双向循环链表的头结点的地址进行备份
	DoubleCirLList_t *Phead=Head->next;
	
	if(Head==Phead)
	{
		printf("双链表为空\n");
		return false;
	}


	if(Phead->next==Phead)
	{
		Head->next=Head;
	}
	else
	{
		Head->next = Phead->next;

		Phead->prev->next=Phead->next;
		Phead->next->prev=Phead->prev;
	}

	Phead->next=NULL;
	Phead->prev = NULL;

	
	free(Phead);

	return true;

}

//尾删
bool DoubleCirLList_TailDel(DoubleCirLList_t *Head)
{
	//对双向循环链表的头结点的地址进行备份
	DoubleCirLList_t *Phead=Head->next;
	DoubleCirLList_t *Bhead=Phead->prev;
	if(Head==Phead)
	{
		printf("双链表为空\n");
		return false;
	}

	if(Phead==Head)
	{
		Head->next=Head;
	}
	else
	{
		Bhead->prev->next=Phead;
		Phead->prev=Bhead->prev;
	}

	Bhead->next=NULL;
	Bhead->prev = NULL;

	free(Bhead);

	return true;
}

//指定删除
bool DoubleCirLList_Del(DoubleCirLList_t *Head, DataType_t dest) 
{
    // 对双链表的头结点的地址进行备份
    DoubleCirLList_t *Phead = Head->next;
    
    if (Phead == NULL) 
	{
        printf("指定双链表为空\n");
        return false;
    }
    
    while (Phead->data != dest) 
	{
        if (Phead->next == Head->next) 
		{
            printf("指删未找到目标节点\n");
            return false;
        }
		Phead = Phead->next;
    }
    
    // 找到目标节点
	if(Phead->next==Phead)
	{
		Head->next=Head;
	}
	else
	{
		if (Phead == Head->next) //目标节点为头
		{
        	Head->next=Phead->next;
    	}
		Phead->prev->next=Phead->next;
		Phead->next->prev=Phead->prev;
	}

	Phead->next = NULL;
	Phead->prev = NULL;


    // 释放节点内存
    free(Phead);

    return true;
}

bool DoubleCirLList_Print(DoubleCirLList_t *Head)
{
	//对双向循环链表的头结点的地址进行备份
	DoubleCirLList_t *Phead = Head;
	
	//判断当前链表是否为空，为空则直接退出
	if (Head->next == Head)
	{
		printf("current linkeflist is empty!\n");
		return false;
	}

	//从首结点开始遍历
	while(Phead->next)
	{
		//把头结点的直接后继作为新的头结点
		Phead = Phead->next;

		//输出头结点的直接后继的数据域
		printf("data = %d\n",Phead->data);

		//判断是否到达尾结点，尾结点的next指针是指向首结点的地址
		if (Phead->next == Head->next)
		{
			break;
		}	
	}

	return true;
}

int main(int argc, char const *argv[])
{

	//1.创建双向循环链表
	DoubleCirLList_t * Manager = DoubleCirLList_Create();
	

	//2.向双向循环链表中的尾部插入新元素
	printf("*********************************尾插********************************\n");
	DoubleCirLList_tailInsert(Manager,5);
	DoubleCirLList_tailInsert(Manager,2);
	DoubleCirLList_tailInsert(Manager,1);
	DoubleCirLList_tailInsert(Manager,4);
	DoubleCirLList_tailInsert(Manager,6);  


	// //3.遍历双向循环链表
	DoubleCirLList_Print(Manager); // -- 5 2 1 4 6
	printf("\n");
	//4.向双向循环链表中的头部插入新元素
	printf("*********************************头插********************************\n");
	DoubleCirLList_HeadInsert(Manager,9);
	DoubleCirLList_HeadInsert(Manager,7);
	DoubleCirLList_HeadInsert(Manager,8);
	DoubleCirLList_HeadInsert(Manager,0);
	DoubleCirLList_HeadInsert(Manager,10);  

	// //5.遍历双向循环链表
	DoubleCirLList_Print(Manager); // --10 0 8 7 9 5 2 1 4 6
	printf("\n");
	//6.删除双向循环链表的元素
	printf("*********************************头删********************************\n");
	DoubleCirLList_HeadDel(Manager);
	DoubleCirLList_HeadDel(Manager);
	DoubleCirLList_HeadDel(Manager);
	DoubleCirLList_HeadDel(Manager);
	DoubleCirLList_HeadDel(Manager);


	DoubleCirLList_Print(Manager);// --5  2  1  4  6 


	//7.指定插入
	printf("*********************************指定插入********************************\n");
	DoubleCirLList_DestInsert(Manager,5,1);
	DoubleCirLList_DestInsert(Manager,2,3);
	DoubleCirLList_DestInsert(Manager,6,7);

	//8.遍历双向循环链表
	DoubleCirLList_Print(Manager); // --5 1 2 3 1 4 6 7
	printf("\n");

	//9.指定删除
	printf("*********************************指定删除********************************\n");
	DoubleCirLList_Del(Manager,5);
	DoubleCirLList_Del(Manager,7);
	DoubleCirLList_Del(Manager,3);

	//10.遍历双向循环链表
	DoubleCirLList_Print(Manager); // -- 1 2 1 4 6 
	printf("\n");

	//11.尾部删除
	printf("*********************************尾删********************************\n");
	DoubleCirLList_TailDel(Manager);
	DoubleCirLList_TailDel(Manager);
	DoubleCirLList_TailDel(Manager);
	DoubleCirLList_TailDel(Manager);

	//12.遍历双向循环链表
	DoubleCirLList_Print(Manager); // --1  
	printf("\n");
	return 0;
}