在编译时确定类型是否为 STL 容器
我想编写一个模板，用于在编译时确定类型是否为 stl 容器.
I would like to write a template that will determine if a type is an stl container at compile time.
我有以下代码:
struct is_cont{};
struct not_cont{};
template <typename T>
struct is_cont { typedef not_cont result_t; };
但我不确定如何为 std::vector 等创建必要的特化...
but I'm not sure how to create the necessary specializations for std::vector<T,Alloc>, deque<T,Alloc>, set<T,Alloc,Comp> etc...
推荐答案
首先，你定义你的主模板，它有一个默认情况下为 false 的成员:
First, you define your primary template, which will have a member which is false in the default case:
template <typename T>
struct is_cont {
static const bool value = false;
};
然后您将为您的容器类型定义部分特化，其值为 true:
Then you will define partial specializations for your container types which have a value of true instead:
template <typename T,typename Alloc>
struct is_cont<std::vector<T,Alloc> > {
static const bool value = true;
};
然后对于要检查的类型 X，像这样使用它
Then for a type X that you want to check, use it like
if (is_cont<X>::value) { ... }
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