I assume that by Form you mean that you are considering to use C++/CLI and .Net.
I'd advice you to use WPF since the graphics will be much easier to implement.
use something like this to parse input (in C#)
string s = "1,2,3,4,5,6";
string[] arrayOfStrings = s.Split(',');
Use C++/CLI to create a .Net .dll assembly for your existing C++ code.
Here is a series showing much of what you need to know to render your graph:
WPF Diagram Designer - Part 4[
^]
Regards
Espen Harlinn