std::iterator_traits

来自cppreference.com

This page has been machine-translated from the English version of the wiki using Google Translate.

The translation may contain errors and awkward wording. Hover over text to see the original version. You can help to fix errors and improve the translation. For instructions click here.

Click here for the English version of this page

 
C++
 
迭代器库
迭代器原语
Original:
Iterator primitives
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
iterator_traits
input_iterator_tag
output_iterator_tag
forward_iterator_tag
bidirectional_iterator_tag
random_access_iterator_tag
iterator
迭代器适配器
Original:
Iterator adaptors
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
reverse_iterator
流迭代器
Original:
Stream iterators
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
istream_iterator
ostream_iterator
istreambuf_iterator
ostreambuf_iterator
迭代器操作
Original:
Iterator operations
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
advance
distance
prev（C++11）
next（C++11）
远程接入
Original:
Range access
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
begin（C++11）
end（C++11）
 
Defined in header <iterator>
template< class Iterator>
struct iterator_traits;
template< class T >
struct iterator_traits<T*>;
template< class T >
struct iterator_traits<const T*>;
std::iterator_traits的类型特征的类，它提供了统一的接口，迭代器类型的属性。这使得它可以实现算法的迭代器.
Original:
std::iterator_traits is the type trait class that provides uniform interface to the properties of iterator types. This makes it possible to implement algorithms only in terms of iterators.
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

目录

[编辑] 会员类型

会员类型
Original:
Member type
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
 Definition
difference_type Iterator::difference_type
value_type Iterator::value_type
pointer Iterator::pointer
reference Iterator::reference
iterator_category Iterator::iterator_category

[编辑] 专业化

此类型的性状可以专门为用户提供的类型，也可以使用作为迭代器。标准库提供了两个偏特化类型的指针，这使得它可以使用所有的基于迭代器的算法与原始指针T *.
Original:
This type trait may be specialized for user-provided types that may be used as iterators. The standard library provides two partial specializations for pointer types T*, which makes it possible to use all iterator-based algorithms with raw pointers.
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

[编辑] T *专业化的成员类型

会员类型
Original:
Member type
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
 Definition
difference_type std::ptrdiff_t
value_type T
pointer T*
reference T&
iterator_category std::random_access_iterator_tag

[编辑] 常量T *专业化的成员类型

会员类型
Original:
Member type
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
 Definition
difference_type std::ptrdiff_t
value_type T
pointer const T*
reference const T&
iterator_category std::random_access_iterator_tag

[编辑] 为例

通用反向（双向迭代器）实现
Original:
general-purpose reverse() implementation for bidirectional iterators
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

#include <iostream>
#include <iterator>
#include <vector>
#include <list>
 
template<class BDIter>
void my_reverse(BDIter first, BDIter last)
{
    typename std::iterator_traits<BDIter>::difference_type n = std::distance(first, last);
    --n;
    while(n > 0) {
        typename std::iterator_traits<BDIter>::value_type tmp = *first;
        *first++ = *--last;
        *last = tmp;
        n -= 2;
    }
}
 
int main()
{
    std::vector<int> v{1,2,3,4,5};
    my_reverse(v.begin(), v.end());
    for(int n : v)
        std::cout << n << ' ';
    std::cout << '\n';
 
    std::list<int> l{1,2,3,4,5};
    my_reverse(l.begin(), l.end());
    for(auto n : l)
        std::cout << n << ' ';
    std::cout << '\n';
 
//    std::istreambuf_iterator<char> i1(std::cin), i2;
//    my_reverse(i1, i2); // compilation error
 
}

Output: 

5 4 3 2 1
5 4 3 2 1

[编辑] 另请参阅
基本的迭代器
Original:
the basic iterator
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

（类模板） [edit]
空类类型用来表示迭代器类别
Original:
empty class types used to indicate iterator categories
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

（类） [edit]
来自“http://zh.cppreference.com/mwiki/index.php?title=cpp/iterator/iterator_traits&oldid=26957”