Converting object to string within a class.

[paul_83uk]

I am trying to convert some old library functions into a class. (i'm trying to force myself to learn OOP)

The Class:

class timestamp {

    protected $input;
    protected $aDate;
    protected $datetime;
    
    public function __construct($input) {
        $this->input = $input;
    }
    
    public function stamp() {
     
        if(strpos($this->input, "-") && !strpos($this->input, ":")) {
                  $aDate = explode("-",$this->input);
                $datetime = mktime(0, 0, 0, $aDate[1], $aDate[2], $aDate[0]);
        }
        elseif(strpos($this->input, ":") && !strpos($this->input, "-")) {
                  $aTime = explode(":",$this->input);
                $datetime = mktime($aTime[0], $aTime[1], $aTime[2], 1, 1, 2007);
        }
        else {
                  $datetime = explode(" ",$this->input);    
                $aDate = explode("-",$datetime[0]);
                $aTime = explode(":",$datetime[1]);
                $datetime = mktime($aTime[0], $aTime[1], $aTime[2], $aDate[1], $aDate[2], $aDate[0]);
            }
    return $datetime;
    }
} 

calling the class produces the error:

Catchable fatal error: Object of class timestamp could not be converted to string

I've worked out its the strpos() function that's causing the error and I understand that you can use __toString() to convert an object to a string but am not sure how to implement it in this set-up.

Any help much appreciated.