回答編集履歴

4

m

2021/01/15 01:16

投稿

yumetodo
yumetodo

スコア5850

test CHANGED
@@ -7,6 +7,8 @@
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  ```cpp
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+ namespace inferior{
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  template<bool b>
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@@ -54,6 +56,8 @@
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  >;
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+ }
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+
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  ```
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3

mi

2021/01/15 01:16

投稿

yumetodo
yumetodo

スコア5850

test CHANGED
@@ -15,20 +15,6 @@
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  template<bool b>
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  using bool_constant = std::integral_constant<bool, b>;
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-
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- template<typename...> struct conjunction : std::true_type {};
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-
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- template<typename B1> struct conjunction<B1> : B1 {};
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-
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- template<typename B1, typename... Bn>
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-
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- struct conjunction<B1, Bn...>
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-
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- : std::conditional_t<bool(B1::value), conjunction<Bn...>, B1> {};
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-
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- template<typename B>
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-
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- struct negation : bool_constant<!bool(B::value)> {};
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  template<typename...>
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2

l

2021/01/14 14:38

投稿

yumetodo
yumetodo

スコア5850

test CHANGED
@@ -77,3 +77,5 @@
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  msvc: [https://github.com/microsoft/STL/blob/ac4fde764ae716512bdd67e0e9577bd53947bc3d/stl/inc/vector#L507-L508](https://github.com/microsoft/STL/blob/ac4fde764ae716512bdd67e0e9577bd53947bc3d/stl/inc/vector#L507-L508)
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+ libstdc++: [https://github.com/gcc-mirror/gcc/blob/d61d2a5f3ce9238bad7cbd7733d90c6ec7ae5fbc/libstdc%2B%2B-v3/include/bits/stl_vector.h#L651-L654](https://github.com/gcc-mirror/gcc/blob/d61d2a5f3ce9238bad7cbd7733d90c6ec7ae5fbc/libstdc%2B%2B-v3/include/bits/stl_vector.h#L651-L654)

1

e

2021/01/14 14:09

投稿

yumetodo
yumetodo

スコア5850

test CHANGED
@@ -2,4 +2,78 @@
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+ イメージとしてはこんなのを作ります。
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+
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+ ```cpp
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+ template<bool b>
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+
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+ using enable_if_t = typename std::enable_if<b, std::nullptr_t>::type;
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+
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+ template<bool b>
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+
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+ using bool_constant = std::integral_constant<bool, b>;
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+
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+ template<typename...> struct conjunction : std::true_type {};
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+
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+ template<typename B1> struct conjunction<B1> : B1 {};
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+
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+ template<typename B1, typename... Bn>
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+
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+ struct conjunction<B1, Bn...>
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+
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+ : std::conditional_t<bool(B1::value), conjunction<Bn...>, B1> {};
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+
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+ template<typename B>
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+
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+ struct negation : bool_constant<!bool(B::value)> {};
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+
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+ template<typename...>
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+
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+ using void_t = void;
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+
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+ template<typename T, typename = void>
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+
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+ struct is_iterator : std::false_type {};
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+ template<typename T>
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+ struct is_iterator<T, void_t<typename std::iterator_traits<T>::iterator_category>>
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+ : std::true_type
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+ {};
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+ template<typename Iterator, bool is_iterator = is_iterator<Iterator>::value>
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+ struct is_input_iterator : std::false_type {};
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+ template<typename Iterator>
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+ struct is_input_iterator<Iterator, true> : std::is_base_of<
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+ std::input_iterator_tag,
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+ typename std::iterator_traits<Iterator>::iterator_category
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+ > {};
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+ template<typename InputIter>
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+ using require_input_iterator = enable_if_t<
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+ inferior::is_input_iterator<InputIter>::value
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+ >;
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+ ```
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+ 実際のSTLの実装を見てみてもそうなっていますね。
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  msvc: [https://github.com/microsoft/STL/blob/ac4fde764ae716512bdd67e0e9577bd53947bc3d/stl/inc/vector#L507-L508](https://github.com/microsoft/STL/blob/ac4fde764ae716512bdd67e0e9577bd53947bc3d/stl/inc/vector#L507-L508)