@[toc](C++:模板偏特化和 decltype(()) 识别表达式的值类别)
#include <iostream>
#include <type_traits>
template<typename T> struct is_lvalue
@[toc](C++:模板偏特化和 decltype(()) 识别表达式的值类别)
#include <iostream>
#include <type_traits>
template<typename T> struct is_lvalue