I am developing using C/C++ window application using winapi. I will be using some standard STL containers and some win api functions provided by windows.h.
I would like use the app on different windows versions such as windows 7 and 10. The apps will be builded for x86 architecture. Would I be getting any issues if app are run on x64?
The apps wont need any permissions to access restricted folders.
At the moment I am not getting any issues running on windows 7. I am just thinking about common possible pitfalls.

Good question. Sad answers so far. I've yet to find a source that runs say a "lint" on c++ code to tell you if you are using depracated API calls. So just like the decades before you test on the versions of Windows you are targeting.

As to 32 to 64 bit, the 64 bit versions of Windows 7 to 10 do run 32 bit apps. This has been true for over a decade so there's little question there.

I'll share I moved to W10 64 bit for reasons like you asked. My clients seem to be on W10 64 bit exclusively.

commented: thank you, for the answer. +3

Sorry for the previous repplies, still having trouble of using new daniweb inteface.

My next question would be can I build one app on my desktop and copy to client desktops? Or do I need to build the apps on client desktop?

A new question usually is best with a new discussion but let's get into "deploying" your app. In Visual C++ 2008 it was possible to create a standalone .exe so there was no installer required. Then again you could have DLLs and other files that need to be deployed so you use your choice of an installer program. There are so many out there but your app usually determines if you need an installer.

We also need to think of our users. The more entry level the user, the more they need to see Setup.exe. They struggle to make a folder for the app and copy in the .exe.