Makefile count how many files

I am making a makefile that compiles some .cpp files but i want it to be "beautiful".
So i try to add current index compiling:
(eg: Compiling 10nth out of 150 total files.)
I successfully did the 10nth out of part, but i cannot find a way to get how many total files are in makefile's directory (in my case how many .cpp's).
What i want is to get this 150 number.
So my Question (and i am really curious WHY no one has ever asked) is, how to get how many .cpp files are in this (makefile's) directory.
I hope this question helps other people as well in the future.