单向链表增删

#include <myhead.h>
typedef struct a
{
	int date;
	struct a *next;
}aa;
//创建节点
aa *Creat()
{
	aa *s=(aa*)malloc(sizeof(aa));
	s->date=0;
	s->next=NULL;
	return s;
}
//头插
aa *insert(aa *head,int num)
{
	aa *s=Creat();
	s->date=num;
	if(NULL==head)
	{
		head=s;
		return head;
	}
	s->next=head;
	head=s;
	return head;
}
//显示
void show(aa *head)
{
	if(head==NULL)
		return;
	aa*p=head;
	while(p!=NULL)
	{
		printf("%d\t",p->date);
		p=p->next;
	}
	puts("");
}
//头删
aa *del(aa *head)
{
	if(NULL==head)
		return head;
	if(head->next==NULL)
	{	
		free(head);
		head=NULL;
		return head;
	}
	aa*p=head;
	head=head->next;
	free(p);
	return head;
}
int main(int argc, const char *argv[])
{
	aa *head=NULL;
	int n;
	printf("please enter n:");
	scanf("%d",&n);
	int num;
	for(int i=0;i<n;i++)
	{
		printf("please enter num:");
		scanf("%d",&num);
		head=insert(head,num);
	}
	show(head);
	head=del(head);
	show(head);
	return 0;
}

双向链表的增删:

#include <myhead.h>
typedef struct a
{
	int date;
	struct a *next;
	struct a *front;
}aa;
//创建节点
aa *Creat()
{
	aa *s=(aa*)malloc(sizeof(aa));
	s->date=0;
	s->next=NULL;
	s->front=NULL;
	return s;
}
//头插
aa *insert(aa *head,int num)
{
	aa *s=Creat();
	s->date=num;
	if(NULL==head)
	{
		head=s;
		return head;
	}
	s->next=head;
	head->front=s;
	head=s;
	return head;
}
//显示
void show(aa *head)
{
	if(head==NULL)
		return;
	aa*p=head;
	while(p!=NULL)
	{
		printf("%d\t",p->date);
		p=p->next;
	}
	puts("");
}
//头删
aa *del(aa *head)
{
	if(NULL==head)
		return head;
	if(head->next==NULL)
	{	
		free(head);
		head=NULL;
		return head;
	}
	aa*p=head;
	head=head->next;
	free(p);
	return head;
}
int main(int argc, const char *argv[])
{
	aa *head=NULL;
	int n;
	printf("please enter n:");
	scanf("%d",&n);
	int num;
	for(int i=0;i<n;i++)
	{
		printf("please enter num:");
		scanf("%d",&num);
		head=insert(head,num);
	}
	show(head);
	head=del(head);
	show(head);
	return 0;
}