The list of the PHP links is recorded

<?PHP/** * DATE:2017/3/31 * time:21:13*/classNode {Private $Data; Private $Next;  Public functionGetNext () {return $this-Next; }     Public functionGetData () {return $this-Data; }     Public functionSetData ($value)    {        $this->data =$value; }     Public functionSetnext ($next)    {        $this-Next=$next; } Public  function__construct ($value,$next){    $this->setdata ($value); $this->setnext ($next);}}classlistnode{Private $header;  Public functionGetHeader () {return $this-Header; }     Public functionSetHeader ($header)    {        $this-Header=$header; }    Public function__construct () {$this->setheader (NewNode (NULL,NULL));}  Public functionAdd$data){        $node=$this-Header;  while($node->getnext ()! =NULL){            $node=$node-GetNext (); }        $node->setnext (NewNode ($data,NULL)); }     Public functionget () {$node=$this-Header; if($node->getnext () = =NULL){                Print("Empty"); }         while($node->getnext ()! =NULL){            Print($node->getnext ()getData ()); if($node->getnext ()->getnext () = =NULL){                 Break; }            $node=$node-GetNext (); }    }     Public functionRemove$data){        $node=$this-Header;  while($node->getnext ()! =NULL&&$node->getnext ()->getdata ()! =$data){            $node=$node-GetNext (); }        if($node->getnext ()! =NULL){            $node->setnext ($node->getnext ()GetNext ()); }//unset ($node->getnext ());    }     Public functionAddafter ($data,$a){    $node=$this-Header;  while($node->getnext () &&$node->getdata ()! =$a){            $node=$node-GetNext (); }        if($node->getnext () = =NULL){            return ; }Else{            $b=$node-GetNext (); $node->setnext (NewNode ($data,$b)); }    }     Public functionAddbefore ($data,$a){        $node=$this-Header; if($node->getdata () = =$a){            NewNode ($data,$node); }         while($node->getnext () &&$node->getnext ()->getdata ()! =$a){            $node=$node-GetNext (); }        if($node->getnext () = =NULL){            return ; }Else{            $b=$node-GetNext (); $node->setnext (NewNode ($data,$b)); }    }     Public  functionUpdata ($data,$a){        $node=$this-Header; if($node->getdata () = =$a){            $node->setdata ($data); }         while($node->getnext () &&$node->getdata ()! =$a){            $node=$node-GetNext (); }        if($node->getdata () = =$a){            $node->setdata ($data); }Else{            return ; }    }}//The following is the test code$a=NewListNode ();$a->add (1);//$a->add (2);//$a->add (3);//$a->add (4);//$a->remove (2);$a->addbefore (6,3);$a->updata (6,22);$a->get ();

The list of the PHP links is recorded