Is it possible to decompile a windows application written in C++?

Question

C++ / C#

The application is not packed with anything, is it possible to get the code?

Answer 1

Can. But not for free.
IDA + Hex-Rays decompiler

Answer 2

C++ source code - unlikely.
You can get machine code - yes, 100% possible. Some very clever disassemblers are able to produce the equivalent code in a high level language, but this is already a powerful sorcery.