On Feb 26, 11:12 pm, Jeff Schwab <j...@schwabcenter.com> wrote:
Alf P. Steinbach wrote:
* Christopher:
reset() { *this = B(); }
I've never seen that before, but it does seem like a neat idea. :)
It seems like it would be (generally speaking) twice as slow as manual
member-by-member initialization, because of (a) the temporary object's
constructor, plus (b) the assignment operator.
Just now I managed to get this working using placement new. Is there
anything bad that can happen with the following code (assuming the
constructor does not throw any exceptions):
class B {
public:
B () { }
~B () { }
void Reset () {
this->~B();
new (this) B();
}
};
I've done a good amount of testing on that just now and it seems to
work fine (even when B has other complex object members, etc.).
Assuming it's safe, it doesn't require you to implement an assignment
operator for complex B's, and doesn't create any temporaries. It seems
like it's just a different way of expressing the following, with the
addition of automatically calling member object destructors and
constructors:
class B {
public:
B () { Init(); }
~B () { Cleanup(); }
void Reset () {
Cleanup();
Init();
}
private:
// these do things:
void Init () { ... }
void Cleanup () { ... }
};
Jason
// ...