Jeremy Siek wrote:
On Friday, March 5, 2004, at 01:42 AM, Jan Gaspar wrote:
________________________________________________ 4. docs: "Type Requirements": doesn't the T need to be DefaultConstructible as well, e.g. to support push_back(void)?
Yes, but DefaultConstructible is needed only if you use such a method. In general it is not needed. For example you can just create empty circular_buffer and use push_back(T&). In this case T doesn't have to be DefaultConstructible.
That means you have to mention this type requirement in the documentation for the push_back() method.
Standard containers do not have push_back()/push_front() methods that take no arguments, so I don't agree with the decision of having them. I would remove them entirely. Moreover, I once had a discussion against having both a foobar() and a foobar(T) or foobar(T&) signature. The argument was that explicit instantiation of the entire class requires both methods to be instantiated so it requires T to be DefaultConstructible even if foobar() is never called. That's why the standard defines, for example, std::vector::resize with a default argument, like this: void resize(size_type sz, T c = T()); this definition effectively works around this kind of problem as the default argument expression is not evaluated unless the method is invoked with less than a full set of arguments. Alberto