From Jason Turner

[ostream.iterator]

C++17 → C++20 3.1 KB 43 lines
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tmp/tmp4mopoafl/{from.md → to.md} RENAMED
@@ -2,91 +2,71 @@
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  `ostream_iterator` writes (using `operator<<`) successive elements onto
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  the output stream from which it was constructed. If it was constructed
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  with `charT*` as a constructor argument, this string, called a
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  *delimiter string*, is written to the stream after every `T` is written.
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- It is not possible to get a value out of the output iterator. Its only
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- use is as an output iterator in situations like
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-
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- ``` cpp
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- while (first != last)
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- *result++ = *first++;
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- ```
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-
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- `ostream_iterator`
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-
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- is defined as:
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  ``` cpp
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  namespace std {
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  template<class T, class charT = char, class traits = char_traits<charT>>
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  class ostream_iterator {
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  public:
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  using iterator_category = output_iterator_tag;
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  using value_type = void;
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- using difference_type = void;
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  using pointer = void;
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  using reference = void;
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  using char_type = charT;
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  using traits_type = traits;
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  using ostream_type = basic_ostream<charT,traits>;
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  ostream_iterator(ostream_type& s);
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  ostream_iterator(ostream_type& s, const charT* delimiter);
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  ostream_iterator(const ostream_iterator& x);
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  ~ostream_iterator();
 
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  ostream_iterator& operator=(const T& value);
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  ostream_iterator& operator*();
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  ostream_iterator& operator++();
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  ostream_iterator& operator++(int);
 
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  private:
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- basic_ostream<charT,traits>* out_stream; // exposition only
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- const charT* delim; // exposition only
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  };
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  }
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  ```
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- #### `ostream_iterator` constructors and destructor <a id="ostream.iterator.cons.des">[[ostream.iterator.cons.des]]</a>
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  ``` cpp
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  ostream_iterator(ostream_type& s);
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  ```
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  *Effects:* Initializes `out_stream` with `addressof(s)` and `delim` with
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- null.
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  ``` cpp
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  ostream_iterator(ostream_type& s, const charT* delimiter);
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  ```
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  *Effects:* Initializes `out_stream` with `addressof(s)` and `delim` with
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  `delimiter`.
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- ``` cpp
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- ostream_iterator(const ostream_iterator& x);
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- ```
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-
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- *Effects:* Constructs a copy of `x`.
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-
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- ``` cpp
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- ~ostream_iterator();
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- ```
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-
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- *Effects:* The iterator is destroyed.
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-
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- #### `ostream_iterator` operations <a id="ostream.iterator.ops">[[ostream.iterator.ops]]</a>
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  ``` cpp
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  ostream_iterator& operator=(const T& value);
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  ```
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  *Effects:* As if by:
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  ``` cpp
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  *out_stream << value;
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- if (delim != 0)
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  *out_stream << delim;
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  return *this;
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  ```
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  ``` cpp
 
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  `ostream_iterator` writes (using `operator<<`) successive elements onto
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  the output stream from which it was constructed. If it was constructed
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  with `charT*` as a constructor argument, this string, called a
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  *delimiter string*, is written to the stream after every `T` is written.
 
 
 
 
 
 
 
 
 
 
 
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  ``` cpp
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  namespace std {
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  template<class T, class charT = char, class traits = char_traits<charT>>
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  class ostream_iterator {
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  public:
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  using iterator_category = output_iterator_tag;
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  using value_type = void;
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+ using difference_type = ptrdiff_t;
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  using pointer = void;
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  using reference = void;
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  using char_type = charT;
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  using traits_type = traits;
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  using ostream_type = basic_ostream<charT,traits>;
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+ constexpr ostream_iterator() noexcept = default;
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  ostream_iterator(ostream_type& s);
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  ostream_iterator(ostream_type& s, const charT* delimiter);
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  ostream_iterator(const ostream_iterator& x);
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  ~ostream_iterator();
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+ ostream_iterator& operator=(const ostream_iterator&) = default;
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  ostream_iterator& operator=(const T& value);
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  ostream_iterator& operator*();
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  ostream_iterator& operator++();
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  ostream_iterator& operator++(int);
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+
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  private:
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+ basic_ostream<charT,traits>* out_stream = nullptr; // exposition only
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+ const charT* delim = nullptr; // exposition only
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  };
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  }
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  ```
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+ #### Constructors and destructor <a id="ostream.iterator.cons.des">[[ostream.iterator.cons.des]]</a>
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  ``` cpp
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  ostream_iterator(ostream_type& s);
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  ```
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  *Effects:* Initializes `out_stream` with `addressof(s)` and `delim` with
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+ `nullptr`.
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  ``` cpp
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  ostream_iterator(ostream_type& s, const charT* delimiter);
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  ```
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  *Effects:* Initializes `out_stream` with `addressof(s)` and `delim` with
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  `delimiter`.
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+ #### Operations <a id="ostream.iterator.ops">[[ostream.iterator.ops]]</a>
 
 
 
 
 
 
 
 
 
 
 
 
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  ``` cpp
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  ostream_iterator& operator=(const T& value);
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  ```
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  *Effects:* As if by:
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  ``` cpp
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  *out_stream << value;
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+ if (delim)
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  *out_stream << delim;
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  return *this;
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  ```
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  ``` cpp