std::remove_extent

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C++
 
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Swap, forward and move
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类型的支持
基本类型
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Basic types
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基本类型
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is_constructible
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is_nothrow_move_constructible		（C++11）
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is_assignable
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is_nothrow_assignable		（C++11）
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is_copy_assignable
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is_move_assignable
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is_nothrow_move_assignable		（C++11）
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rank（C++11）
extent（C++11）
类型的修改
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Type modifications
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remove_cv
remove_const
remove_volatile		（C++11）
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add_cv
add_const
add_volatile		（C++11）
（C++11）
（C++11）
make_signed（C++11）
make_unsigned（C++11）
remove_reference（C++11）
add_lvalue_reference
add_rvalue_reference		（C++11）
（C++11）
remove_pointer（C++11）
add_pointer（C++11）
remove_extent（C++11）
remove_all_extents（C++11）
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Type transformations
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aligned_storage（C++11）
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键入特征常数
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Type trait constants
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integral_constant（C++11）
 
Defined in header <type_traits>
template< class T >
struct remove_extent;
 （C++11 起）
如果T是某些类型的数组X，提供成员typedeftype等于X，否则type是T。需要注意的是，如果T是一个多维数组，只有第一个维度被删除.
Original:
If T is an array of some type X, provides the member typedef type equal to X, otherwise type is T. Note that if T is a multidimensional array, only the first dimension is removed.
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目录

[编辑] 会员类型

姓名
Original:
Name
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 Definition
type
T的元素的类型
Original:
the type of the element of T
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[编辑] 可能的实现

template<class T>
struct remove_extent { typedef T type; };
 
template<class T>
struct remove_extent<T[]> { typedef T type; };
 
template<class T, std::size_t N>
struct remove_extent<T[N]> { typedef T type;};

[编辑] 为例

#include <iostream>
#include <iterator>
#include <algorithm>
#include <type_traits>
 
template<class A>
typename std::enable_if< std::rank<A>::value == 1 >::type
print_1d(const A& a)
{
    copy(a, a+std::extent<A>::value,
         std::ostream_iterator<typename std::remove_extent<A>::type>(std::cout, " "));
    std::cout << '\n';
}
 
int main()
{
    int a[][3] = {{1,2,3},{4,5,6}};
//  print_1d(a); // compile-time error
    print_1d(a[1]);
}

Output: 

4 5 6

[编辑] 另请参阅

（C++11）
检查如果一个类型是数组类型
Original:
checks if a type is an array type
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（类模板） [edit]
（C++11）
获得一个数组类型的尺寸
Original:
obtains the number of dimensions of an array type
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（类模板） [edit]
（C++11）
获得一个数组类型的大小，沿着指定的尺寸
Original:
obtains the size of an array type along a specified dimension
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（类模板） [edit]
（C++11）
 removes all extents from the given array type
（类模板） [edit]
来自“http://zh.cppreference.com/mwiki/index.php?title=cpp/types/remove_extent&oldid=26787”