This is based off general programming knowledge, as I have never used C++, but I think it is referring to a highly-modulated programming style that uses many general functions.

I.e., instead of writing a few quick lines of code to perform bisection search in the middle of logic flow, you create a general bisection search function and implement that.

This leads to high productivity "a statement per function", and makes code cleaner and easier to update, but can substantially increase overhead costs.