<?php
// The linked list node
class node {
    public $id; // node id
    public $name; // The name of the node
    public $next; // Under the 1 node
   
    public function __construct($id, $name) {
        $this->id = $id;
        $this->name = $name;
        $this->next = null;
    }
}
// Singly linked lists
class singelLinkList {
    private $header; // Chain header node
   
    // A constructor
    public function __construct($id = null, $name = null) {
        $this->header = new node ( $id, $name, null );
    }

    // Gets the length of the list
    public function getLinkLength() {
        $i = 0;
        $current = $this->header;
        while ( $current->next != null ) {
            $i ++;
            $current = $current->next;
        }
        return $i;
    }

    // Add node data
    public function addLink($node) {
        $current = $this->header;
        while ( $current->next != null ) {
            if ($current->next->id > $node->id) {
                break;
            }
            $current = $current->next;
        }
        $node->next = $current->next;
        $current->next = $node;
    }

    // Delete the list node
    public function delLink($id) {
        $current = $this->header;
        $flag = false;
        while ( $current->next != null ) {
            if ($current->next->id == $id) {
                $flag = true;
                break;
            }
            $current = $current->next;
        }
        if ($flag) {
            $current->next = $current->next->next;
        } else {
            echo " Not found id=" . $id . " The node! <br>";
        }
    }

    // Access list
    public function getLinkList() {
        $current = $this->header;
        if ($current->next == null) {
            echo (" The list is empty !");
            return;
        }
        while ( $current->next != null ) {
            echo 'id:' . $current->next->id . '   name:' . $current->next->name . "<br>";
            if ($current->next->next == null) {
                break;
            }
            $current = $current->next;
        }
    }

    // Get the node name
    public function getLinkNameById($id) {
        $current = $this->header;
        if ($current->next == null) {
            echo " The list is empty !";
            return;
        }
        while ( $current->next != null ) {
            if ($current->id == $id) {
                break;
            }
            $current = $current->next;
        }
        return $current->name;
    }

    // Update node name
    public function updateLink($id, $name) {
        $current = $this->header;
        if ($current->next == null) {
            echo " The list is empty !";
            return;
        }
        while ( $current->next != null ) {
            if ($current->id == $id) {
                break;
            }
            $current = $current->next;
        }
        return $current->name = $name;
    }
}
$lists = new singelLinkList ();
$lists->addLink ( new node ( 5, 'eeeeee' ) );
$lists->addLink ( new node ( 1, 'aaaaaa' ) );
$lists->addLink ( new node ( 6, 'ffffff' ) );
$lists->addLink ( new node ( 4, 'dddddd' ) );
$lists->addLink ( new node ( 3, 'cccccc' ) );
$lists->addLink ( new node ( 2, 'bbbbbb' ) );
$lists->getLinkList ();
echo "<br>----------- Remove nodes --------------<br>";
$lists->delLink ( 5 );
$lists->getLinkList ();
echo "<br>----------- Update node name --------------<br>";
$lists->updateLink ( 3, "222222" );
$lists->getLinkList ();
echo "<br>----------- Get the node name --------------<br>";
echo $lists->getLinkNameById ( 5 );
echo "<br>----------- Gets the length of the list --------------<br>";
echo $lists->getLinkLength ();
?>