"StrToDouble" - someone please?

OK, here's my problem:

I have this function
function TForm1.Romberg1Integrand(x: Double): Double;

In Delphisourcecode this function shall looks this:

function TForm1.Romberg1Integrand(x: Double): Double;
begin
Romberg1Integrand := x*x;
end;

My problem is, that I want to define the Romber1Integrand in runtime: The user may select a function (in this case it is "x*x") from a ComboBox and the string shall be used as the function. Any idea on how to do this, it's really important!

Any help is apreciated, thanks in advance.

Assuming you have a finite (and reasonable) number of functions you want to implement, then one trick is to set-up a separate pascal function for each one, and then use type fType = function(d:double):double to form an array of pointers to them so that you can index them from the selected variable of the combo box.

Alternatively, simply use a series of if/then statements to compute the appropriate value, given the function required.

Neville

I dont think I really understand what your driving at! Are you saying that in the combobox the user can select RombergIntegrand1 and then the program calls that function, or does the user select X*X?