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;
}