C++ concepts: RandomAccessIterator
From cppreference.com
A RandomAccessIterator is a BidirectionalIterator that can be moved to point to any element in constant time.
A standard pointer is an example of a type that satisfies this concept.
[edit] Requirements
In addition to the above requirement, for a type It to be an RandomAccessIterator, instances a, b, i, and r of It must:
Expression | Return | Equivalent expression | Notes |
---|---|---|---|
r += n | It& | if(n>=0) while(n--) ++r; |
|
i + n | It | It temp = i; return i += n; |
|
n + i | It | i + n | |
r -= n | It& | return r += -n; | |
i - n | It | It temp = i; return i -= n; |
|
n - i | It | i - n | |
b - a | difference | n | returns n such that a+n==b |
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) |
[edit] Table Notes
- It is the type implementing this concept
- T is the type std::iterator_traits<It>::value_type
- reference is the type std::iterator_traits<It>::reference
- difference is the type std::iterator_traits<It>::difference_type
- i, a, b are objects of type It or const It
- r is a value of type It&
- n is an integer of type difference
The above rules imply that RandomAccessIterator also implements LessThanComparable.