C++ Iterator Library - bidirectional_iterator_tag

Description

It used to identify the category of an iterator as a bidirectional iterator and bidirectional iterator support at least one the following operations.

property valid expressions

It is a default-constructible, copy-constructible, copy-assignable and destructible

X a;


X b(a);

b = a;

It 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

It 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

It 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 after being both increased.

++a

a++

*a++

It can be decremented (if a dereferenceable iterator value precedes it).

--a

a--

*a--

property	valid expressions
It is a default-constructible, copy-constructible, copy-assignable and destructible	`X a;` `X b(a);` `b = a;`
It 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`
It 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`
It 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 after being both increased.	`++a` `a++` `*a++`
It can be decremented (if a dereferenceable iterator value precedes it).	`--a a--` `*a--`
Lvalues are swappable.	`swap(a,b)`

Following is the declaration for std::bidirectional_iterator_tag.

struct bidirectional_iterator_tag {}

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