What is the program of choice? Is it really as simple as Objective-C for apple and .net for windows? It seems to me that a program could be written in C++ and be used on any operating system. That leads me to GUI's also. Can a program be written in C++, used in mac os and windows os with the main changes being GUI language/configuration? Mac uses cocoa and windows uses .net? Ive heard the term "language binder". Im trying to ask different people so I can formulate my own conclusion?
If you want to develop in C++, Qt framework is a great choice.
Qt is a cross platform framework while .net and cocoa are not.
Qt has a rich GUI library and an IDE (Qt Creator). Also supports something like SQL database connection and many other features.