双向链表的查找、插入和删除

双向链表的查找

#include 
#include 

typedef int data_t;

typedef struct node{
	data_t data;
	struct node *prior;
	struct node *next;
}dlistnode;

dlistnode* dlist_create(){
	dlistnode *H,*r,*p;
	int n;
	
	if((H=(dlistnode *)malloc(sizeof(dlistnode)))==NULL)
	{
		puts("malloc failed");
		return NULL;
	}

	H->prior = H;
	H->next = H;
	r = H;

	while(1){
		printf("please input(-1 exit):");
		scanf("%d",&n);
		if(n==-1)
			break;

		if((p=(dlistnode *)malloc(sizeof(dlistnode)))==NULL)
		{
			printf("malloc failed\n");
			return NULL;
		}

		p->data=n;
		p->prior=r;
		p->next=r->next;
		r->next=p;
		H->prior=p;
		r=p;
	}

	return H;
}

void dlist_show(dlistnode* H)
{
	dlistnode *p;

	p=H->next;
	while(p!=H)
	{
		printf("%d ",p->data);
		p=p->next;
	}
	putchar(10);
}

dlistnode* dlist_get(dlistnode *H,int pos)
{
	int i=0;
	dlistnode *p=H;

	if(pos <0){
		puts("pos < 0,invalid!");
		return NULL;
	}

	while(inext;
		i++;
		if(p==H){
			puts("pos > length,invalid");
			return NULL;
		}

	}
	return p;
}

int main(int argc, const char *argv[])
{
	dlistnode *H,*p;
	int pos;


	H=dlist_create();
	dlist_show(H);

	while(1)
	{
		printf("input pos(-1 exit):");
		scanf("%d",&pos);
		if(pos==-1)
			break;
		p=dlist_get(H,pos);

		if(p)
			printf("%d\n",p->data);
	}
	return 0;
}

双向链表的插入

从指定节点前面插入数据

#include 
#include 

typedef int data_t;

typedef struct node{
	data_t data;
	struct node *prior;
	struct node *next;
}dlistnode;

dlistnode* dlist_create(){
	dlistnode *H,*r,*p;
	int n;
	
	if((H=(dlistnode *)malloc(sizeof(dlistnode)))==NULL)
	{
		puts("malloc failed");
		return NULL;
	}

	H->prior = H;
	H->next = H;
	r = H;

	while(1){
		printf("please input(-1 exit):");
		scanf("%d",&n);
		if(n==-1)
			break;

		if((p=(dlistnode *)malloc(sizeof(dlistnode)))==NULL)
		{
			printf("malloc failed\n");
			return NULL;
		}

		p->data=n;
		p->prior=r;
		p->next=r->next;
		r->next=p;
		H->prior=p;
		r=p;
	}

	return H;
}

void dlist_show(dlistnode* H)
{
	dlistnode *p;

	p=H->next;
	while(p!=H)
	{
		printf("%d ",p->data);
		p=p->next;
	}
	putchar(10);
}

dlistnode* dlist_get(dlistnode *H,int pos)
{
	int i=0;
	dlistnode *p=H;

	if(pos <0){
		puts("pos < 0,invalid!");
		return NULL;
	}

	while(inext;
		i++;
		if(p==H){
			puts("pos > length,invalid");
			return NULL;
		}

	}
	return p;
}

int dlist_insert(dlistnode *H,data_t value,int pos)
{
	dlistnode *p,*q;

	p=dlist_get(H,pos);
	if(p==NULL)
		return -1;

	if((q=(dlistnode *)malloc(sizeof(dlistnode)))==NULL)
	{
		printf("malloc failed\n");
		return -1;
	}
	
	q->data = value;

	q->prior=p->prior;
	q->next=p;
	p->prior->next=q;
	p->prior = q;

	return 0;
}

int main(int argc, const char *argv[])
{
	dlistnode *H;
	int pos;
	data_t data;


	H=dlist_create();
	dlist_show(H);

	while(1)
	{
		printf("input pos(-1 exit):");
		scanf("%d",&pos);
		if(pos==-1)
			break;
		printf("input data:");
		scanf("%d",&data);
		dlist_insert(H,data,pos);
	}
	dlist_show(H);

	return 0;
}

双向链表的删除

#include 
#include 

typedef int data_t;

typedef struct node{
	data_t data;
	struct node *prior;
	struct node *next;
}dlistnode;

dlistnode* dlist_create(){
	dlistnode *H,*r,*p;
	int n;
	
	if((H=(dlistnode *)malloc(sizeof(dlistnode)))==NULL)
	{
		puts("malloc failed");
		return NULL;
	}

	H->prior = H;
	H->next = H;
	r = H;

	while(1){
		printf("please input(-1 exit):");
		scanf("%d",&n);
		if(n==-1)
			break;

		if((p=(dlistnode *)malloc(sizeof(dlistnode)))==NULL)
		{
			printf("malloc failed\n");
			return NULL;
		}

		p->data=n;
		p->prior=r;
		p->next=r->next;
		r->next=p;
		H->prior=p;
		r=p;
	}

	return H;
}

void dlist_show(dlistnode* H)
{
	dlistnode *p;

	p=H->next;
	while(p!=H)
	{
		printf("%d ",p->data);
		p=p->next;
	}
	putchar(10);
}

dlistnode* dlist_get(dlistnode *H,int pos)
{
	int i=0;
	dlistnode *p=H;

	if(pos <0){
		puts("pos < 0,invalid!");
		return NULL;
	}

	while(inext;
		i++;
		if(p==H){
			puts("pos > length,invalid");
			return NULL;
		}

	}
	return p;
}

int dlist_delete(dlistnode *H,int pos)
{
	dlistnode *p;

	p=dlist_get(H,pos);
	if(p==NULL)
		return -1;

	p->prior->next = p->next;
	p->next->prior = p->prior;

	free(p);
	p=NULL;

	return 0;
}

int main(int argc, const char *argv[])
{
	dlistnode *H;
	int pos;

	H=dlist_create();
	dlist_show(H);

	while(1)
	{
		printf("input pos(-1 exit):");
		scanf("%d",&pos);
		if(pos==-1)
			break;
		dlist_delete(H,pos);
	}
	dlist_show(H);

	return 0;
}