我有一组基于整数N的类型模板,还有一个类来包含所有满足N <= K且N >= 0的类型,类似于:
template <int N> struct T { int i; }
template <int N> struct TContainer{
std::vector<T<N>> vec;
TContainer<N - 1> prev;
template <int target_n> TContainer<target_n> & get() { return prev.get(); }
template <> TContainer<N> & get<N>() { return *this; }
};
template <> struct TContainer<0>{
std::vector<T<N>> vec;
template <int target_n> TContainer<target_n> & get() { }
template <> TContainer<0> & get<0>() { return *this; }
};
class ContainsAll{
TContainer<K> my_data;
int my_instance_data;
};
ContainsAll是否有一种foreach函数,能够接受一个模板成员函数,以便对所有N的每个元素执行操作?类似于:
template<int N>
void for_each(TContainer<N> & container, template_function){
for(auto it = container.vec.begin(); it != container.vec.end(); ++it){
template_function(*it);
}
for_each<K - 1>(container.prev, template_function);
}
template<> void for_each<0>(TContainer<0> & container, template_function){
for(auto it = container.vec.begin(); it != container.vec.end(); ++it){
template_function(*it);
}
}
所以我可以做到:
template <int N> add_to_T(T<N> & in){
in.i += my_instance_data;
}
for_each(my_container, add_to_T);