A LegacyRandomAccessIterator is a LegacyBidirectionalIterator that can be moved to point to any element in constant time.
A pointer to an element of an array satisfies all requirements of LegacyRandomAccessIterator.
The type It
satisfies LegacyRandomAccessIterator if.
It
satisfies LegacyBidirectionalIterator And, given.
value_type
, the type denoted by std::iterator_traits<It>::value_type
difference_type
, the type denoted by std::iterator_traits<It>::difference_type
reference
, the type denoted by std::iterator_traits<It>::reference
i
, a
, b
, objects of type It
or const It
r
, a value of type It&
n
, an integer of type difference_type
The following expressions must be valid and have their specified effects.
Expression | Return type | Operational semantics | Notes |
---|---|---|---|
r += n |
It& |
difference_type m = n; if (m >= 0) while (m--) ++r; else while (m++) --r; return r; |
|
a + n
|
It |
It temp = a; return temp += n; |
|
r -= n | It& |
return r += -n; | The absolute value of n must be within the range of representable values of difference_type . |
i - n | It | It temp = i; return temp -= n; | |
b - a | difference_type | return n; | Precondition:
Postcondition:
|
i[n] | convertible to reference
| *(i + n) | |
a < b | contextually convertible to bool
|
b - a > 0 | Strict total ordering relation:
|
a > b | contextually convertible to bool
| b < a | Total ordering relation opposite to a < b |
a >= b | contextually convertible to bool
| !(a < b) | |
a <= b | contextually convertible to bool
| !(a > b) |
The above rules imply that LegacyRandomAccessIterator also implements LessThanComparable.
A mutable LegacyRandomAccessIterator is a LegacyRandomAccessIterator that additionally satisfies the LegacyOutputIterator requirements.
ConceptFor the definition of
where the exposition-only concept | (since C++20) |
specifies that a BidirectionalIterator is a random-access iterator, supporting advancement in constant time and subscripting (concept) |
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