DLLs, Header Files, OCX's, Adding to Visual C++ Express Project

[Tester2]

Found some neat graphing software for 2D and 3D applications at CodeProject. Looking forward to using with MS VC++ Express, which I just downloaded and installed. Can I do this? Is it legal? The creator offers what seem to be some options, but I'm not sure the header files are compliant with MS VC++ (Express) classes. For that reason, I'm contemplating the DLL option with one, 3D graphing "adder", and an OCX option with the 2D graphing software. How can I add these to the toolbox under Windows XP, or is that not possible? Do I need to go with the header file option only, or are the class library issues obstructive? (Don't want this installation to crash, or to violate a license merely by using an OCX or DLL instead of a header file.)

Thanks!

[thines01]

Yes, downloading the Express edition is legal.
Yes, downloading someone's public domain code is legal.

All forms of C++ can be compiled with the Express edition.
If the product is available in some type of library form (DLL, OCX, LIB, etc), go ahead and use that if you don't need to see the source code.

BUT since you are using C++, you might still need the header file.
If it is a dot net DLL, you can use it without a header file.

[Tester2]

The code I'm referencing is described here (including downloadables):

http://www.codeproject.com/KB/openGL/ntgraph3d_atl.aspx

.

I've been away from C++, dll's, and structures too long. Quite honestly, because of the dll origin, I'm not sure how to refer to the structure data type in defining a structure of that type with a variable.

MS VC++ Express isn't recognizing the structure members that are referenced in the sample code at the above reference when I embed the sample code from the origin link (CodeProject) above in a button click event. The debugger immediately takes issue with that, and repeats similar complaints regarding attempts to define structure members for the data plot structure.

That seems to suggest that even with the dll registered from the binary download file, and the header file from another download file from the same place visible in the project, I need to somehow tell the compiler, at the very least, that I'm using a structure defined within the dll for three dimensional plotting. (I don't know how to do that.)

At this point, I'm not sure how to access the dll, although I've told VC++ that it exists, and that it's registered as a resource. I also wonder if simply having the downloaded header file visible in the project definition diagram in the upper left of the VC++ screen under the form directory in which I make the call is enough.

If you can straighten me out on this one, feel free to put a gold star on your refrigerator.

Thanks!