std::common_type是C++标准库中的一个模板类,用于确定一组类型的公共类型。其目的是为了在编译时确定这些类型的最通用的公共类型,以便在进行类型转换或模板参数推导时使用。 具体来说,std::common_type的目的是为了解决在模板编程中需要处理不同类型的情况。当我们需要对不同类型的对象进行操作时,可能需要进行类型转...
type C; // Base typedef std::common_type<Derived*,Base*>::type D; // Base* typedef std::common_type<const int,volatile int>::type E; // int std::cout << std::boolalpha; std::cout << "typedefs of int:" << std::endl; std::cout << "A: " << std::is_same<int,A>:...
std::common_type<std::chrono::duration> specializes the std::common_type trait (class template specialization) std::common_type<std::chrono::time_point> specializes the std::common_type trait (class template specialization) Possible implementation | // primary template (used for zero types) temp...
#include <type_traits> template <typename T, typename U> typename std::common_type<T, U>::type max(T a, U b) { return b < a ? a : b; } 上面的函数, 使用下面的代码输出 Copy Highlighter-hljs/// 代码1 std::cout << tt::max(1.3, 2) << "\n\n"; /// 代码2 std::co...
两边的类型。也就是C ? A : B表达式如果成立的话，结果的类型就是A和B两个类型的common type。
Otherwise, if there is a user specialization for std::common_type<T1, T2>, that specialization is used; Otherwise, if std::decay<decltype(false ? std::declval<T1>() : std::declval<T2>())>::type is a valid type, the member type denotes that type, see the conditional operator; ...
std::common_type<T1,T2>的实现怎么会是这样的呢?这样写的话那不是type永远都是declval<T2>()的类型?! tempalte <typename T1, typename T2> struct common_type<T1,T2> { typedef decltype(true ? declval<T1>() : declval<T2>()) type; };c++...
(constT&t,constS&s)->typenamestd::common_type<T,S>::type{typedeftypenamestd::common_type<T,S>::typeCommon;returnCommon(t)-Common(s);}intmain(){usingnamespacestd::literals;constexprautoms=30ms;constexprautous=1100us;constexprautodiff=durationDiff(ms, us);std::cout<<ms<<" - "<<us...
std::common_type(std::chrono::duration) std::common_type(std::chrono::time_point) std::conditional std::conjunction std::const_mem_fun1_ref_t std::const_mem_fun1_t std::const_mem_fun_ref_t std::const_mem_fun_t std::const_pointer_cast std::cref std::ctime std::current_exception...
std::common_type(std::chrono::duration) std::common_type(std::chrono::time_point) std::conditional std::conjunction std::const_mem_fun1_ref_t std::const_mem_fun1_t std::const_mem_fun_ref_t std::const_mem_fun_t std::const_pointer_cast std::cref std::ctime std::current_exception...