From Jason Turner

[iterator.operations]

C++17 → C++20 1.8 KB 23 lines
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Archived: C++17 | C++20
Markdown: C++17 | C++20
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  1. tmp/tmp9uukqh3f/{from.md → to.md} +9 -11
tmp/tmp9uukqh3f/{from.md → to.md} RENAMED
@@ -9,31 +9,29 @@ iterators they use `++` to provide linear time implementations.
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  ``` cpp
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  template<class InputIterator, class Distance>
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  constexpr void advance(InputIterator& i, Distance n);
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  ```
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- *Requires:* `n` shall be negative only for bidirectional and random
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- access iterators.
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- *Effects:* Increments (or decrements for negative `n`) iterator
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- reference `i` by `n`.
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  ``` cpp
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  template<class InputIterator>
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  constexpr typename iterator_traits<InputIterator>::difference_type
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  distance(InputIterator first, InputIterator last);
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  ```
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- *Effects:* If `InputIterator` meets the requirements of random access
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- iterator, returns `(last - first)`; otherwise, returns the number of
 
 
 
 
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  increments needed to get from `first` to `last`.
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- *Requires:* If `InputIterator` meets the requirements of random access
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- iterator, `last` shall be reachable from `first` or `first` shall be
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- reachable from `last`; otherwise, `last` shall be reachable from
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- `first`.
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-
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  ``` cpp
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  template<class InputIterator>
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  constexpr InputIterator next(InputIterator x,
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  typename iterator_traits<InputIterator>::difference_type n = 1);
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  ```
 
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  ``` cpp
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  template<class InputIterator, class Distance>
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  constexpr void advance(InputIterator& i, Distance n);
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  ```
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+ *Preconditions:* `n` is negative only for bidirectional iterators.
 
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+ *Effects:* Increments `i` by `n` if `n` is non-negative, and decrements
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+ `i` by `-n` otherwise.
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  ``` cpp
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  template<class InputIterator>
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  constexpr typename iterator_traits<InputIterator>::difference_type
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  distance(InputIterator first, InputIterator last);
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  ```
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+ *Preconditions:* `last` is reachable from `first`, or `InputIterator`
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+ meets the *Cpp17RandomAccessIterator* requirements and `first` is
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+ reachable from `last`.
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+
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+ *Effects:* If `InputIterator` meets the *Cpp17RandomAccessIterator*
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+ requirements, returns `(last - first)`; otherwise, returns the number of
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  increments needed to get from `first` to `last`.
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  ``` cpp
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  template<class InputIterator>
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  constexpr InputIterator next(InputIterator x,
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  typename iterator_traits<InputIterator>::difference_type n = 1);
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  ```