The Template Method -- Rainer Grimm
With or without actual templates:
The Template Method
by Rainer Grimm
From the article:
The key idea of the Template Method is easy to get. You define the skeleton of an algorithm that consists of a few typical steps. Implementation classes can only override the steps but cannot change the skeleton. The steps are often called hook methods...

Const... times four:
constexpr keeps getting more and more powerful with each release:
Playing the classics, at arm's length...
When having the "last word" makes stuff go faster...
As Crocodile Dundee famously said, "That's not a loop, that's a loop." Just programmers having fun: