Chapter 21 // Exercise 3 - Principles & Practice Using C++

In this exercise I am using Visual Studio 2019 and a modified version of the std_lib_facilities header found here.

Chapter 21 // Exercise 3

Implement count() yourself. Test it.

Github: https://github.com/l-paz91/principles-practice/blob/master/Chapter%2021/Exercise%203

I originally returned a number however I then had a look at the actual implementation of std::count and used difference_type instead:
https://en.cppreference.com/w/cpp/algorithm/count