shared_ptr to weak_ptr

#include <stdio.h>
#include <memory>

class Base
{
public:
	virtual void print() {
		printf("Base");
	}
};

class Derived :
	public Base
{
public:
	virtual void print() override {
		printf("Derived");
	}
};



int main()
{
	//todo lessons
	std::shared_ptr<Derived> der{ new Derived };
	std::weak_ptr<Base> base = std::dynamic_pointer_cast<Base>(der);

	if (auto lock = base.lock()) {
		lock->print();
	} else {
		printf("could not lock");
	}


	char a[256];
	scanf_s("%s", a, 256);
	return 0;
}