🚀 go-pugleaf

I'm trying to learn C++, which seems to go against all the conventions
I learned in school, back when there was core memory and we used
keypunch cards, tapes, etc.  What I would like to do is write an
application that will take information from a database or databases,
perform some calculations, and produce a customer quote, PO's,
invoices, etc.

I need the database portion of the program to provide manual updates
as well as an automatic update where it will read a file from a vendor
(MS Works spreadsheet or Excel spreadsheet), and replace any outdated
price list items with the updated information.

The user interface would consist of a spreadsheet type screen that
would let me enter part numbers and quantities and would calculate my
cost, customer cost, and generate customer quotes, purchase orders,
invoices and other reports I design.

Optionally, it would be nice to have a graphic interface that would
allow me to enter a drawing (residential blueprints) either:
	o manually, or
	o through a scanner and then allow me to digitize certain
	   points on the drawing (to provide scale information for
	   example).
Then I would like to be able to click on a location on the drawing,
tell the program what I want to go in a particular spot, and have it
calculate the length of wire runs.  Perhaps a PCB routing type of
algorithm.

Can anyone point me to code samples or fragments in the public domain
that will help me accomplish the above?  Preferrably, well documented
examples.

Thanks in advance,

Steve