std::ostream_iterator
STD：：Ostream[医]迭代器
| Defined in header | | |
|---|---|---|
| template< class T, class CharT = char, class Traits = std::char_traits<CharT> > class ostream_iterator : public std::iterator<std::output_iterator_tag, void, void, void, void> | | (until C++17) |
| template< class T, class CharT = char, class Traits = std::char_traits<CharT>> class ostream_iterator; | | (since C++17) |
std::ostream_iterator是一次过OutputIterator，它写入类型的连续对象。T进入std::basic_ostream对象，并使用operator<<可选分隔符字符串在每次写入操作后写入输出流。当迭代器%28(不管是否取消引用)分配给%29时，将执行写入操作。递增std::ostream_iterator是个禁止行动。
在典型的实现中，std::ostream_iterator是指向关联std::basic_ostream和指向分隔符字符串中的第一个字符的指针。
写字的时候，std::ostreambuf_iterator更有效，因为它避免了每个字符构造和销毁哨兵对象一次的开销。
成员类型
| Member type | Definition |
|---|---|
| char_type | CharT |
| traits_type | Traits |
| ostream_type | std::basic_ostream<CharT, Traits> |
成员函数
| (constructor) | constructs a new ostream_iterator (public member function) |
|---|---|
| (destructor) | destructs an ostream_iterator (public member function) |
| operator= | writes a object to the associated output sequence (public member function) |
| operator* | no-op (public member function) |
| operator++operator++(int) | no-op (public member function) |
成员类型
| Member type | Definition |
|---|---|
| value_type | void |
| difference_type | void |
| pointer | void |
| reference | void |
| iterator_category | std::output_iterator_tag |
注意：在C++17之前，这些成员类型必须通过从std::iterator<std::output_iterator_tag,void,void,void,void>...
例
二次
#include <iostream>
#include <sstream>
#include <iterator>
#include <numeric>
int main()
{
std::istringstream str("0.1 0.2 0.3 0.4"
std::partial_sum(std::istream_iterator<double>(str),
std::istream_iterator<double>(),
std::ostream_iterator<double>(std::cout, " ")
}
二次
产出：
二次
0.1 0.3 0.6 1
二次
另见
| ostreambuf_iterator | output iterator that writes to std::basic_streambuf (class template) |
|---|---|
| istream_iterator | input iterator that reads from std::basic_istream (class template) |
| std::experimental::ostream_joiner (library fundamentals TS v2) | An output iterator that writes successive elements into an output stream, separating adjacent elements with a delimiter (class template) |
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