src/Datastructure/Stackqueue/Queue.php
public function dequeue() {
        if (null === $this->queue) return null;
        if ($this->tail > $this->head) return null;
        $item = $this->queue[$this->tail];
        $this->tail++;
        return $item;
    }
public function dequeue() {
        if (null === $this->queue) return null;
        if ($this->tail > $this->head) return null;
        $item = $this->queue[$this->tail];
        $this->tail++;
        return $item;
    }
public function dequeue ( ) { if ( null === $ this -> queue ) return null ; if ( $ this -> tail > $ this -> head ) return null ; $ item = $ this -> queue [ $ this -> tail ] ; $ this -> tail ++ ; return $ item ; }
this method removes the first element from the queue and returns it

@return int
this method removes the first element from the queue and returns it