Visual Studio "Run button" changed to "Attach to a process"

Question

I am trying to run a C code in microsoft visual studio 2015. For some reason, the run bottom is changed to "Attach to a process". And when I attach any of the process, the process wouldn't start to run (command prompt would'nt open).

That's a picture of my visual studio and the attach to process window:

Answer 1

May be because the code you have compiled gives only a Dynamic Link Library (DLL) file. So you need to attach it to a process (.exe file) which will load the (DLL) for execution.

Also, why 0 projects?