是带有operator（）或函数的stl算法类

Question

Recently I've taken C++ quiz and here is question from it:

Select all concepts that are represented in STL by templated classes

1. Containers
2. Iterators
3. Functors
4. Algorithms
5. Exceptions

Obviously 1,2 and 3 are templated classes, but what about algorithms? I never thought about it, but algorithms can be templated functions, and also can be templated classes with operator().

Though, I think it does not matter and rather silly question, I'm interested in answer, because I only have number of my mistakes in quiz without knowing where I was right and where wrong.

tl;dr: Are STL algorithms functions or classes with operator()?

Thank you.

Answer 1

They're function templates.

See Algorithms library