Go to the resharper web page for more info.
Supported languages : C#, VB.NET, C++, XAML, JavaScript, TypeScript, JSON, XML, HTML, CSS, ASP.NET, ASP.NET MVC, Protobuf, NAnt and MSBuild scripts
ReSharper was originally created to work with C# (thus the name ReSharper) .
ReSharper really helps in code refactoring, static analysis, code generation and lot more (again, see the ReSharper web site)
ReSharper now supports C++; it has more or less the same features than the C# ReSharper .
Because the language is not the same (C++ does not support reflection, which greatly helps the C# version) some features are not available on the C++ version (I don't have specific examples in mind).
Personally, I really love the static analysis part of ReSharper C++.
I've only started using C# in my job and still need to learn to use ReSharper with it.