c++ class templates - container vs other categories

I feel most introductory texts and most interview questions follow the "container" theme. There's at least one field of type T. This prompted to rethink the Usage, industry adoption and justification of c++ class templates.

Most well-known libraries define class templates. They don't all follow that "theme".

In enterprise application teams, however, I don't see a lot of brand-new templates created from scratch. (Let's not hypothesize why.) A lot of template class concretized; perhaps (presumably) some new templates created based on some proven designs, with low risk and low complexity. I do see some templates created in a local library, such as a MatrixDouble or a SmartPtr, but few.

Bottom line -- you seldom create your own new class template. If you do, then I would venture to say the first template you /popularize/ is likely a container.

The class templates I created so far --

* matrix of any type like string or number, with user-defined size

* circular array