Visual Studio 2015 by default does not install C++. Try reinstalling VS2015 with Visual C++ components selected.
Hello! Look at https://answers.unrealengine.com/questions/325377/error-occurred-while-i-tried-to-generate-c-project.html
The full mesage: An error occurred while trying to generate project files.
Running C:/Program Files (x86)/Epic Games/4.11/Engine/Binaries/DotNET/UnrealBuildTool.exe -projectfiles -project=“C:/Users/Adrian/Documents/Unreal Projects/MyProject1/MyProject1.uproject” -game -progress -2015
Visual C++ 2015 toolchain does not appear to be correctly installed. Please verify that “Common Tools for Visual C++ 2015” was selected when installing Visual Studio 2015.
Discovering modules, targets and source code for game…
UnrealBuildTool Exception: ERROR: Failed to find cl.exe in the default toolchain directory C:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\Tools…/…/VC/bin/x86_amd64\cl.exe. Please verify that “Common Tools for Visual C++ 2015” was selected when installing Visual Studio 2015.