2月3日作业

1.编程实现单向循环链表的头插，头删、尾插、尾删

尾插/头插，头删，尾删：

头文件：


#ifndef __HEAD_H_
#define __HEAD_H_


#include<stdio.h>
#include<string.h>
#include<stdlib.h>

enum {FALSE=-1,SUCCESS};
typedef int datatype;
typedef struct node
{
	//数据域
	datatype data;
	//指针域
	struct node *next;
}*linklist;


linklist creat();
linklist insert_head(linklist head,datatype element);
void output(linklist head);
linklist insert_rear(linklist head,datatype element);
linklist delete_head(linklist head);
linklist delete_rear(linklist head);


#endif

主函数：

#include"head.h"


int main(int argc, const char *argv[])
{
	//头插
	linklist head=NULL;
	int n;
	printf("please enter n:");
	scanf("%d",&n);
	datatype element;
	for(int i=0;i<n;i++)
	{
		printf("please enter %d element:",i+1);
		scanf("%d",&element);
		//头插
		head=insert_head(head,element);
		//尾插
//		head=insert_rear(head,element);

	}
	output(head);
	
	//头删
	head=delete_head(head);
	output(head);

	//尾删
	head=delete_rear(head);
	output(head);

	return 0;
}

自定义函数：

#include"head.h"


int main(int argc, const char *argv[])
{
	//头插
	linklist head=NULL;
	int n;
	printf("please enter n:");
	scanf("%d",&n);
	datatype element;
	for(int i=0;i<n;i++)
	{
		printf("please enter %d element:",i+1);
		scanf("%d",&element);
		//头插
		head=insert_head(head,element);
		//尾插
//		head=insert_rear(head,element);

	}
	output(head);
	
	//头删
	head=delete_head(head);
	output(head);

	//尾删
	head=delete_rear(head);
	output(head);






	
	return 0;
}
ubuntu@ubuntu:~/寒假作业/2.3$ cat test.c 
#include"head.h"

linklist creat()
{
	linklist head=(linklist)malloc(sizeof(struct node));
	if(head==NULL)
		return NULL;
	head->data=0;
	head->next=head;
	return head;
}
//头插
linklist insert_head(linklist head,datatype element)
{
	linklist s=creat();
	s->data=element;
	if(head==NULL)
	{
		head=s;
		return head;	
	}
	linklist p=head;
	while(p->next!=head)
		p=p->next;
	s->next=head;
	head=s;
	p->next=head;
	return head;
}

void output(linklist head)
{
	linklist s=head;
	do
	{
		printf("%-4d",s->data);
		s=s->next;
	}while(s!=head);
	puts("");
}

//尾插
linklist insert_rear(linklist head,datatype element)
{
	linklist s=creat();
	s->data=element;
	linklist p=head;
	if(head==NULL)
	{
		head=s;
		return head;	
	}
	while(p->next!=head)
		p=p->next;
	p->next=s;
	s->next=head;

	return head;
}

//头删
linklist delete_head(linklist head)
{
	if(head==NULL)
		return head;
	linklist del=head;	
	linklist p=head;
	while(p->next!=head)
		p=p->next;
	head=head->next;
	p->next=head;
	free(del);
	del=NULL;
	return head;
}

//尾删
linklist delete_rear(linklist head)
{
	if(head==NULL)
		return head;
	linklist p=head;
	if(head->next==head)
	{
		free(head);
		head=NULL;
		return head;
	}
	while(p->next->next!=head)
		p=p->next;
	linklist del=p->next;
	p->next=head;
	free(del);
	del=NULL;
	return head;
}