数据结构线性表代码

<?php
class ArrayList{
 private $list;
 private $size;
 public function __construct()
 {
 $this->list=array();
 $this->size=0;
 }
 //初始化链表
 public function InitList(){
 $this->list=array();
 $this->size=0;
 }
 //删除链表
 public function destoryList(){
 if (isset($this->list)){
 unset($this->list);
 $this->size=0;
 }
 }
 //清空链表
 public function clearList(){
 if (isset($this->list)){
 unset($this->list);
 }
 $this->list=array();
 $this->size=0;
 }
 //判断链表是否为空
 public function emptyList(){
 if (isset($this->list)){
 if ($this->size==0){
 return true;
 }else{
 return false;
 }
 }
 }
 //链表长度
 public function lengthList(){
 if (isset($this->list)){
 return $this->size;
 }else{
 return false;
 }
 }
 //取元素
 public function getElem($i){
 if ($i<1||$i>$this->size){
 die('failed');
 }
 if (isset($this->list)&&is_array($this->list)){
 return $this->list[$i-1];
 }
 }
 //是否在链表中
 public function locateElem($e){
 if (isset($this->list)&&is_array($this->list)){
 for ($i=0;$i<$this->size;$i++){
 if ($this->list[$i]==$e){
 return $i+1;
 }
 return 0;
 }
 }
 }
 //前驱
 public function priorElem($i){
 if ($i<1||$i>$this->size){
 die('failed');
 }
 if ($i==1){
 die('no prior');
 }
 if (isset($this->list)&&is_array($this->list)){
 return $this->list[$i-2];
 }
 }
 //后继
 public function nextElem($i){
 if ($i<1||$i>$this->size){
 die('failed');
 }
 if ($i==$this->size){
 die('no next');
 }
 if (isset($this->list)&&is_array($this->list)){
 return $this->list[$i];
 }
 }
 //插入元素
 public function insertList($i,$e){
 if ($i<1||$i>$this->size){
 die('failed');
 }
 if (isset($this->list)&&is_array($this->list)){
 if ($this->size==0){
 $this->list[0]=$e;
 $this->size++;
 }else{
 for($j=$this->size-1;$j>=$i;$j--){
 $this->list[$j]=$this->list[$j-1];
 }
 $this->list[$i-1]=$e;
 $this->size++;
 }
 }
 }
 //删除元素
 public function deleteList($i){
 if ($i<1||$i>$this->size){
 die('failed');
 }
 if (isset($this->list)&&is_array($this->list)){
 if ($i==$this->size){
 unset($this->list[$i-1]);
 }else{
 unset($this->list[$i-1]);
 for ($j=$i;$j<$this->size;$j++){
 $this->list[$j-1]=$this->list[$j];
 }
 }
 $this->size--;
 }
 }
 //遍历
 public function printList(){
 if (isset($this->list)&&is_array($this->list)){
 foreach ($this->list as $value) {
 echo $value.' ';
 }
 }
 }
}