Std::iterator

Features

++it, it++가 정의 될 것. 단 ++it는 자기 자신의 타입의 리퍼런스를 반환해야함.
"*it = 값" 이 정의되어야함. (중요)
다시 이전 iterator를 접근하는 일은 없음.

Category

Category to which the iterator belongs to. It must be one of the following iterator tags:

Iterator category					Defined operations
ContiguousIterator	RandomAccessIterator	BidirectionalIterator	ForwardIterator	InputIterator	read increment (without multiple passes)
			ForwardIterator		increment (with multiple passes)
					decrement
					random access
					contiguous storage
Iterators that fall into one of the above categories and also meet the requirements of OutputIterator are called mutable iterators.
OutputIterator					write increment (without multiple passes)

Contiguous Iterator

RandomAccess Iterator

Bidirectional Iterator

Forward Iterator

cppreference.com - C++ concepts: ForwardIterator

Forward iterators are iterators that can be used to access the sequence of elements in a range in the direction that goes from its beginning towards its end.

Performing operations on a forward iterator that is dereferenceable never makes its iterator value non-dereferenceable. This enables algorithms that use this category of iterators to use multiple copies of an iterator to pass more than once by the same iterator values.

All bidirectional and random-access iterators are also valid forward iterators.

There is not a single type of forward iterator: Each container may define its own specific iterator type able to iterate through it and access its elements. But all forward iterators support -at least- the following operations:

property	valid expressions
Is default-constructible¹, copy-constructible, copy-assignable and destructible.	`X a;` `X b(a);` `b = a;`
Can be compared for equivalence using the equality/inequality operators (meaningful when both iterator values iterate over the same underlying sequence).	`a == b` `a != b`
Can be dereferenced as an rvalue (if in a dereferenceable state).	`*a` `a->m`
For mutable iterators (non-constant iterators): Can be dereferenced as an lvalue (if in a dereferenceable state).	`*a = t`
Can be incremented (if in a dereferenceable state). The result is either also dereferenceable or a past-the-end iterator. Two iterators that compare equal, keep comparing equal when both are increased.	`++a` `a++` `*a++`
Lvalues are swappable. (C++11)	`swap(a,b)`

Std::iterator

Features

Category

Contiguous Iterator

RandomAccess Iterator

Bidirectional Iterator

Forward Iterator

Input Iterator

Output Iterator

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Class & Function References

References