C语言双向环形链表

本是古典何须时尚 2023-06-13 06:27 21阅读 0赞

#include<stdio.h>
    #include<stdlib.h>
    
    struct list 
    {
        
    	struct list *pr;
    	int data;
    	struct list *next;
    };
    
    struct list* Create()
    {
        
    	struct list *head,*pnew,*pre;
    	int i;
    	int number = 5;
    	head = (struct list*)malloc(sizeof(struct list));
    	head->data = 0;
    	head->next = NULL;
    	pre = head;
    	for(i=1;i<number;i++)
    	{
        
    		pnew = (struct list*)malloc(sizeof(struct list));
    		pnew->pr = pre;
    		pnew->data = i;
    		pnew->next = NULL;
    		pre->next = pnew;
    		pre = pre->next;
    	}
    	pnew->next = head;
    	head->pr = pnew;
    	return head;
    }
    
    struct list* Insert(struct list *head,int pos)
    {
        
    	struct list *pnew,*end;
    	int i;
    	pnew = (struct list*)malloc(sizeof(struct list));
    	pnew->data = 100;
    	if(pos==0)
    	{
        
    		head->pr->next = pnew;
    		pnew->next = head;
    		head->pr = pnew;
    		pnew->pr = head->pr;
    		head = pnew;
    	}
    	else
    	{
        
    		end = head;
    		if(pos>=2)
    		{
        
    			for(i=0;i<(pos-1);i++)
    			{
        
    				end = end->next;
    				if(end->next==NULL)
    					break;
    			}
    		}
    		pnew->pr = end;
    		pnew->next = end->next;
    		if(end->next==NULL)
    			pnew->next = NULL;
    		else
    			end->next->pr = pnew;	
    		end->next = pnew;
    	}
    	return head;
    }
    
    struct list* Delete(struct list *head,int pos)
    {
        
    	struct list *obj;
    	int i;
    	if(pos==0)
    	{
        
    		obj = head;
    		head->pr->next = head->next;
    		head->next->pr = head->pr;
    		head = head->next;
    	}
    	else
    	{
        
    		obj = head->next;
    		if(pos>=2)
    		{
        
    			for(i=0;i<(pos-1);i++)
    				obj = obj->next;
    		}
    		obj->pr->next = obj->next;
    		obj->next->pr = obj->pr;
    		if(obj==head)
    			head = head->next;//如果被删除的是head，那么新head为原head下一个链节
    		
    	}
    	free(obj);
    	return head;
    }
    
    int Check(struct list *head,int pos)
    {
        
    	int i;
    	if(pos>=1)
    	{
        
    		for(i=0;i<pos;i++)
    			head = head->next;
    	}
    	return head->data;
    }
    
    void Modify(struct list *head,int pos,int dat)
    {
        
    	int i;
    	if(pos>=1)
    	{
        
    		for(i=0;i<pos;i++)
    			head = head->next;
    	}
    	head->data = dat;
    }	
    
    void Print(struct list *head)//只打印有效数据
    {
        
    	struct list *temp;
    	temp = head;
    	printf("%d\n",temp->data);
    	do
    	{
        
    		temp = temp->next;
    		printf("%d\n",temp->data);
    	}while(temp->next!=head);//如果再次循环到head处，则停止输出
    }
    
    void Print_all(struct list *head)//这个是打印全部数据，也就是一个无限循环
    {
        
    	printf("%d\n",head->data);
    	head = head->next;
    }
    
    void main()
    {
        
    	struct list *head;
    	int data;
    	head = Create();
    	data = Check(head,0);
    	printf("%d\n",data);
    }