线性表之链表

#include "stdafx.h"
#include <malloc.h>
#include <iostream>
#include <stdio.h>
#include <math.h>
#include <stdlib.h>

using namespace std;

typedef int DataType;

struct LNode{
	DataType data;
	struct LNode *next;

};

typedef struct	LNode *LinkList;

int getElem(LinkList L,int i,DataType *e)
{
	//找到第i个元素并复制给e
	int j = 0;
	LinkList p = L->next;
	while(p&&j<i)
	{
		p = p->next;
		j++;
	}
	if(!p ||j>i) return -1;
	*e = p->data;
	return 1;
}
//在第i个位置插入e
int  insert(LinkList L,int i ,DataType e)
{
	//先找到第i-1个节点
	LinkList p = L,s;
	int j = 0;
	while( p && j<i-1)
	{
		p = p->next;
		j++;
	}
	if(!p ||j>i+1) return -1;
	//生成新节点
	s = (LinkList)malloc(sizeof(struct LNode));
	s->data = e;
	s->next = p->next;
	p->next = s;
	return 1;

}

int listDelete(LinkList L,int i,DataType *data)
{
	int j =0;
	LinkList p = L,q;
	while(p->next&&j<i-1)
	{
		p=p->next;
		j++;
	}
	if(!p->next||j>i-1) return -1;
	q = p->next;
	p->next = q->next;
	*data = q->data;
	free(q);
	return 1;
}

/*int deleteByTail(LinkList *L)//位置并不好找
{
	LNode *p =(*L)->next;
	while(p->next != NULL) p =p->next; 
	
}*/
//在表头输入插入n个元素的值
/*int insertByHead(LinkList *L,int n)
{
	//先建立一个带头结点的单链表
	*L = (LinkList)malloc(sizeof(struct LNode));
	(*L)->next =NULL;

	//循环输入插入
	LinkList p ;
	for(int i=n;i>0;i--)
	{
		//生成新的节点
		p = (LinkList)malloc(sizeof(struct LNode));
		scanf("%d",&p->data);
		p->next = (*L)->next;
		(*L)->next = p;
	}

}*/

int insertByTail(LNode **head,DataType data)
{
	/*LNode *p,*temp;
	if((*L)->next != NULL) {
		*p = (*L)->next->next;
	}
	//LNode *p = (*L)->next,*temp;
	temp = (LNode*)malloc(sizeof(struct LNode));
	temp ->data = data;
	while(p->next != NULL) p = p->next;
	p->next = temp;
	temp->next = NULL;
	return 0;*/
	//判断链表是否为空
	LNode *phead = *head;
	LNode *pTemp = new LNode;
	pTemp = phead;

	LNode *insert_node = new LNode;
	insert_node->data = data;
	insert_node ->next = nullptr;
	while(phead != nullptr) phead = phead->next;//这句话会报错
	phead->next = insert_node;
	*head = pTemp;
	return 1;
}

int showList(LinkList L)
{
	int num = 0;
	LinkList p =L->next;
	while(p)
	{
		if(num)//如果不是表中的第一个元素
		{
			putchar(' ');
		}
		num++;
		printf("%d",p->data);
		p= p->next;
	}
	if(num ==0)
		return 0;
	else 
		return num;
}
/*void main()
{//最后运行不出结果
	LinkList L;
	insertByTail(&L,1);
	insertByTail(&L,2);
	showList(L);
}*/