Example of simple implementation of circular linked list function in PHP

<?php
class node{
  public $data;
  public $link;
  public function __construct($data=null,$link=null){
    $this->data=$data;
    $this->link=$link;
  }
}
class cycleLinkList{
  public $head;
  public function __construct($data,$link=null){
    $this->head=new node($data,$link);
    $this->head->link=$this->head;
  }
  public function insertLink($data){
    $p=new node($data);
    $q=$this->head->link;
    $r=$this->head;
    if($q==$r)
    {
      $q->link=$p;
      $p->link=$q;
      return;
    }
    while($q!=$this->head){
      $r=$q;$q=$q->link;
    }
    $r->link=$p;
    $p->link=$this->head;
  }
}
$linklist=new cycleLinkList(1);
for($i=2;$i<11;$i++){
   $linklist->insertLink($i);
}
$q=$linklist->head->link;
echo $linklist->head->data;
while($q!=$linklist->head){
  echo $q->data;
  $q=$q->link;
}
echo "<br>--------------------------<br>";
$p=$linklist->head;
$r=$p;
$n=10;
$i=2;
while($n)
{
    while(0!=$i){
    $r=$p;$p=$p->link;
    $i--;
    }
    echo $p->data;
    $r->link=$p->link;
    $tmp=$p;
    $p=$p->link;
    unset($tmp);
    $n--;
    $i=2;
}

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