I have recently gone from Code::Blocks to Visual Studio, and in Code::Blocks one could just add a class and then include it straight away. However, whenever I do the same in
If your problem is still there it's certainly because you are trying to compile a different version from your current settings.
For example if you set your Additional Include Directories
in Debug x64, be sure that you are compiling with the same configuration.
Check this: Build > Configuration Manager... >
There is problably something like this in your active solution configuration: Debug x86 (Win32) platform
.