Question

I’m trying to extend my CI with a custom library that I plan on using for calculating the time value of money. The issue is whenever I load the class I get an internal server error, and I’m not quite sure why. Also, if there are any other suggestions, please let me know.

Thanks

Here is the controller where I’m trying to load the library.

class Timevalueshow extends Controller{

    $params = array('years' => 0, 
                    'rate' => 0, 
                    'principle' => 0, 
                    'periods' => 0, 
                    'isCont' => true
                    );

    $this->load->library('timevalue',$params);

    function index(){       

        $this->load->view('Timevalueshow_view');
        return true;
    }

}

Here is the library, saved under application/libraries

class Timevalue{

    private $years;
    private $rate;
    private $principle;
    private $periods;
    private $isCont;


    //zeros to test
    function Timevalue($params) {  
        $this->years = $params['years'];  
        $this->rate = $params['rate'];
        $this->principle = $params['principle'];  
        $this->periods = $params['periods']; 
        $this->isCont = $params['isCont'];
    }
    //General Getters
    function getYears(){
        return $this->years;
    }
    function getRate(){
        return $this->rate;
    }
    function getPrinciple(){
        return $this->principle;
    }
    function getPeriods(){
        return $this->periods;
    }

    //Factors
    function FVFactor(){
        if($this->isCont){
            $new_rate = $this->rate / $this->periods;
            $new_periods = $this->periods * $this->years;
            return pow(1+$new_rate,$new_periods);
        }
        else{
            return exp($this->rate*$this->years);
        }   
    }

    function PVFactor(){
        if($this->isCont){
            return pow($this->FVFactor(),-1);
        }
        else{
            return pow($this->FVFactor(),-1);
        }
    }

    //General Print
    function leprint(){
        echo "<br />Years: " . $this->years;  
        echo "<br />Rate(dec): " . $this->rate;
        echo "<br />Principle: $" . $this->principle;  
        echo "<br /># of Periods: " . $this->periods;
        echo "<br />isCont: " . ($this->isCont ? "True" : "False");
    }
}

Answer 1

Your controller needs a constructor. It should look like this:

class Timevalueshow extends Controller{

    function __construct(){
        parent::__construct();
        $params = array('years' => 0, 
            'rate' => 0, 
            'principle' => 0, 
            'periods' => 0, 
            'isCont' => true
        );
        $this->load->library('timevalue',$params);
    }

    function index(){       
        $this->load->view('Timevalueshow_view');
    }
}

Only PHP5 uses the __construct function. In PHP4 it should look like this:

function Timevalueshow(){
    parent::Controller();
}