Determines the size of a string expression containing a number when using Val().
% = Val?(a$)
Val?(a$) returns 0, if a$ contains no characters that can be interpreted as numbers.
Debug.Show
Trace Val?("12345") // Prints 5
Trace Val?("3.00 DM") // Prints 4
Trace Val?("Hallo GFA") // Prints 0
{Created by Sjouke Hamstra; Last updated: 25/10/2014 by James Gaite}