C++模板:如何确定类型是否适合子类化

#include <type_traits>

class Base {};

class Derived : public Base {};

int main() {
    bool isDerived = std::is_base_of<Base, Derived>::value;
    // isDerived为true，说明Derived是Base的子类
    return 0;
}

template<typename T>
struct is_base_of_base {
    template<typename Base>
    static std::true_type test(const Base*);
    
    template<typename>
    static std::false_type test(...);
    
    static constexpr bool value = decltype(test<T>(nullptr))::value;
};

class Base {};

class Derived : public Base {};

int main() {
    bool isDerived = is_base_of_base<Derived>::value;
    // isDerived为true，说明Derived是Base的子类
    return 0;
}

template<typename T>
void check_base_of() {
    static_assert(std::is_base_of<Base, T>::value, "T must be derived from Base");
}

class Base {};

class Derived : public Base {};

int main() {
    check_base_of<Derived>();
    // 编译通过，说明Derived是Base的子类
    return 0;
}