_toString() PHP function
Here is my _toString() function.  I can't find anything wrong with it but I keep getting an error in my browser when I try to echo an obj of this class saying "Catchable fatal error: Object of class Fraction could not be converted to string in."

    public function _toString ()
    {
        $str = "";
        if(($this->num/$this->den) >= 1)
        {
            $tmp = ((int)($this->num/$this->den));
            $str .= "{$tmp} ";    
        }

        if ($this->num%$this->den != 0)
        {
            $tmp =$this->num % $this->den;
            $str .= "{$tmp} / {$this->den}";
        }
        return $str;
    }

Could it be something wrong with my function or is it something else?  Thanks.

(This is for a fraction class I am trying to represent in a string.  $num is the numerator and $den is the denominator)
_toString() PHP function
===

Here is my _toString() function.  I can't find anything wrong with it but I keep getting an error in my browser when I try to echo an obj of this class saying "Catchable fatal error: Object of class Fraction could not be converted to string in."

    public function _toString ()
    {
        $str = "";
        if(($this->num/$this->den) >= 1)
        {
            $tmp = ((int)($this->num/$this->den));
            $str .= "{$tmp} ";    
        }

        if ($this->num%$this->den != 0)
        {
            $tmp =$this->num % $this->den;
            $str .= "{$tmp} / {$this->den}";
        }
        return $str;
    }

Could it be something wrong with my function or is it something else?  Thanks.

(This is for a fraction class I am trying to represent in a string.  $num is the numerator and $den is the denominator)