双链表基本操作

#include <stdlib.h>
#include <iostream>
using namespace std;

#define null 0
#define MAXSIZE 50

struct strlnode
{
	int data;
	struct strlnode *plast;
	struct strlnode *pnext;
};

void create(struct strlnode **p, int x)  /*创建双链表(表头节点)*/
{
	struct strlnode *q;

	q = (struct strlnode *)malloc(sizeof(struct strlnode));
	q->data = x;
	q->plast = null;
	q->pnext = null;

	*p = q;

	return;
}

void insertnode(struct strlnode **p, int i, int x) /* 在链表第i个位置插入数据等于x的节点 */
{
	/* 代码在这里实现 */
	if (p == NULL || *p == NULL )
	{
		cout<<"error!"<<endl;
		return ;
	}
	if (i < 0)
	{
		printf("i must be larger than 0 !");
		return ;
	}
	struct strlnode *pTemp = *p;//指向头结点
	struct strlnode *newNode;

	newNode = (struct strlnode *)malloc(sizeof(struct strlnode));
	newNode->data = x;

	if (0 == i)//插入到头结点
	{

		newNode->pnext = pTemp;
		pTemp->plast = newNode;
		newNode->plast = NULL;
		*p = newNode;
		return;
	}

	int k = i;
	while(k > 1 && pTemp->pnext != NULL)//查找第i个结点
	{
		pTemp = pTemp->pnext;
		k--;
	}

	if (pTemp->pnext == NULL)
	{
		pTemp ->pnext = newNode;
		newNode->plast = pTemp;
		newNode->pnext = NULL;
	}
	else
	{
		newNode->pnext = pTemp->pnext;
		newNode->plast = pTemp;
		pTemp->pnext->plast = newNode;
		pTemp->pnext = newNode;

	}
	return ;

}

void deletenode(struct strlnode **p, int i) /* 删除链表中第i个节点 */
{
	/* 代码在这里实现 */
	if (p == NULL || *p == NULL )
	{
		printf("error!");
		return ;
	}
	if (i < 0)
	{
		printf("i must be larger than 0 !");
		return ;
	}

	if (i == 0 && (*p)->pnext == NULL)//仅有一个结点
	{
		free(*p);
		p = NULL;
		return;
	}
	struct strlnode *pTemp = *p;//指向头结点
	int k = i;
	while(k > 1 && pTemp != NULL)//查找第i-1个结点
	{
		pTemp = pTemp->pnext;
		k--;
	}

	struct strlnode *qTemp;
	qTemp = pTemp ->pnext;
	if (qTemp->pnext != NULL)
	{
		pTemp->pnext = qTemp->pnext;
		qTemp->pnext->plast = pTemp;
		free(qTemp);
	}
	else
	{
		pTemp->pnext = qTemp->pnext;
		free(qTemp);
	}

}

int getnodenum(struct strlnode **p)  /*获取链表中节点个数*/
{
	int nodenum = 0;
	/* 代码在这里实现 */
	if (NULL == p)
	{
		return nodenum;
	}
	struct strlnode *pTemp ;
	pTemp = *p;
	while(pTemp != NULL)
	{
		nodenum++;
		pTemp = pTemp->pnext;
	}

	return nodenum;
}

void bignumberplus(struct strlnode **plus, struct strlnode **p, struct strlnode **q) /* 使用链表实现大整数相加 */
{
	/* 代码在这里实现 */
	if (NULL == p || NULL == *p)
	{
		*plus = *q;
		return;
	}
	if (NULL == q || NULL == *q)
	{
		*plus = *p;
		return;
	}
    struct strlnode *pTemp = *p;
    struct strlnode *qTemp = *q;
    while(NULL != pTemp->pnext)
    {
        pTemp = pTemp->pnext;
    }
    while(NULL != qTemp->pnext)
    {
        qTemp = qTemp->pnext;
    }
	int carry = 0;

	struct strlnode *sum = (struct strlnode *)malloc(sizeof(struct strlnode));

	sum->data = (pTemp->data + qTemp ->data)%10;
	carry = (pTemp->data + qTemp ->data)/10;
	sum->plast = NULL;
	sum->pnext = NULL;
	pTemp = pTemp->plast;
	qTemp = qTemp->plast;

	struct strlnode *temp;
	while(NULL != pTemp && NULL != qTemp)
	{
		temp = (struct strlnode *)malloc(sizeof(struct strlnode));
		temp->data = (pTemp->data + qTemp ->data + carry)%10;
		carry = (pTemp->data + qTemp ->data + carry)/10;

		temp->pnext= sum;
		temp->plast = NULL;
		sum->plast = temp;

		pTemp = pTemp->plast;//链表均向前移动
		qTemp = qTemp->plast;
		sum = sum->plast;
	}
	while(NULL != pTemp)
	{
		temp = new struct strlnode;
		temp->data = (pTemp->data + carry)%10;
		carry = (pTemp->data + carry)/10;

        temp->pnext= sum;
        temp->plast = NULL;
        sum->plast = temp;

		pTemp = pTemp->plast;
		sum = sum->plast;
	}
	while(NULL != qTemp)
	{
		temp = new struct strlnode;
		temp->data = (qTemp ->data + carry)%10;
		carry = (qTemp ->data + carry)/10;

        temp->pnext= sum;
        temp->plast = NULL;
        sum->plast = temp;

		qTemp = qTemp->plast;
		sum = sum->plast;
	}
	while (carry != 0)
	{
		temp = new struct strlnode;
		temp->data = carry%10;
		carry /= 10;

        temp->pnext= sum;
        temp->plast = NULL;

		sum->plast = temp;
        sum = sum->plast;

	}
    *plus = sum;
	return ;

}

void readtolnode(struct strlnode **p, int *a, int size)  /* 将数组写入链表中，链表中的数据的先后顺序和数组中的顺序要保持一致 */
{
	int j = 0;
	int data = 0;
	struct strlnode *s = *p;

	s->data = *(a + (size-1));

	for(j = 2; j < (size+1); j++)
	{
		data = *(a + (size-j));
		insertnode(p, 0, data);
	}

	return;
}

void writetosqlist(int *a, struct strlnode *p)  /* 将链表写入数组中，数组中的数据的先后顺序和链表中的顺序要保持一致 */
{
	int j = 0;
	struct strlnode *s = p;

	while(s != null)
	{
		*(a + j) = s->data;
		s = s->pnext;
		j++;
	}

	return;
}