c++ - How can I delete a undeclared pointer?

Question

If the new operator was written in a function argument or constructor argument like:

Foo* f = new Foo(new Baz(0, 0));
// how to delete "new Baz(0, 0)"?
delete f;

I know it can be written to:

Baz* b = new Baz(0, 0)
Foo* f = new Foo(b);
delete b;
delete f;

But it became complicated, is there any better way?

Should I do something like this:

Class Foo {
private:
    Baz* _b;
public:
    Foo(Baz* b) : _b(b) {}
    ~Foo() {
        delete _b;
    }
}
// so that when I delete foo will also delete baz;

Answer 1

Following my own recommendation about the rule of zero and using std::unique_ptr, I would do something like this:

class Foo
{
public:
    Foo(int a, int b)
        baz_{ std::make_unique<Baz>(a, b) }
    {
    }

private:
    std::unique_ptr<Baz> baz_;
};

And

auto foo = std::make_unique<Foo>(0, 0);

With this the foo object own its own unique Baz object.

---

If you want Foo to by copyable then use std::shared_ptr and std::make_shared instead.