public function push(): void
    {
        $this->stack[$this->current + 1] = $this->stack[$this->current];

        ++$this->current;
    }
public function push(): void
    {
        $this->stack[$this->current + 1] = $this->stack[$this->current];

        ++$this->current;
    }
public function push ( ) : void { $ this -> stack [ $ this -> current + 1 ] = $ this -> stack [ $ this -> current ] ; ++ $ this -> current ; }
Add a new elements into the stack.
Add a new elements into the stack .