Conventions

To use the algorithms, you have to keep a few rules in your head.

The algorithms are defined in various headers.

<algorithm>:
Contains the general algorithms.

<numeric>:
Contains the numeric algorithms. Many of the algorithms have the name suffix _if and _copy.

_if:
The algorithm can be parametrized by a predicate.

_copy:
The algorithm copies its elements in another range.

Algorithms like auto num = std::count(InpIt first, InpIt last, const T& val) return the number of elements that are equal to val. num is of type iterator_traits<InpIt>::difference_type. You have the guarantee that num is sufficient to hold the result. Because of the automatic return type deduction with auto, the compiler will give you the right types.

🔑 If the container uses an additional range, it has to be valid
The algorithm std::copy_if uses an iterator to the beginning of its destination range. This destination range has to be valid.

ℹ️ Naming conventions for the algorithms
I use a few naming conventions for the type of arguments and the return type of the algorithms to make them easier to read.

Name	Description
InIt	[Input iterator]
FwdIt	[Forward iterator]
BiIt	[Bidirectional iterator]
UnFunc	[Unary callable]
BiFunc	[Binary callable]
UnPre	[Unary predicate]
BiPre	[Binary predicate]
Search	The searcher encapsulates the search algorithm.
ValType	From the input range automatically deduced value type.
ExePol	Execution policy

Signature of the algorithms