C ++：当临时std :: map超出范围时，将释放std :: map的项

我是C ++非用户用户，我只是在尝试一些好玩的事，而且遇到了麻烦，我想我做错了什么。 I have a std::map of my own classes (std::map<MyClass*, MyClass*>) and I am trying to filter out a subset, store it as a temporary (local instance) std::map<MyClass*, MyClass*>. The problem is, that when the tempo...