class foo {
public:
void reset() {
a0.clear();
a1.clear();
}
private:
std::set<int> a0, a1;
std::set<int> b0;
};
// |||||||||||||
// vvvvvvvvvvvvv
class reflefoo {
public:
void reset() {
// resets a0, a1 and a2. b0 is untouched
for (auto col : reflefoo::some_group_id)
col.reset();
}
private:
some_group_id { std::set<int> a0, a1, a2; }
std::set<int> b0;
};