Reference wrappers `std::reference_wrapper`

Primarily used to feed references to function templates that take their parameter by value.

Function Type Wrappers `std::function`

to use callable objects as first-class objects.

Auxiliary Functions

Processing the Mininum and Maximum

min / max,
minmax returns both minumum and maximum.

`std::swap`

An overload for arrays is provided.

`std::rel_pos`

deprecated in C++20 in favor of three-way comparison operator.