问题描述
是否有标准容器具有与 vector<T> 相同的通用 API，但通过直接默认构造填充新位置?
Is there a standard container that has the same general API as vector<T> but that populates new locations via direct default construction?
背景:
我有一个不允许复制但有一个默认构造函数的类型，我真正想做的是:
I have a type that disallows copying but has a default constructor and what I really want to do is this:
vector<NoCopy> bag(some_size);
// use bag[i]'s
return; // bag & contents get correctly cleaned up.
但是，这不起作用，因为 vector<T>(int) 是根据默认构造一个对象然后将其复制到每个新位置来实现的.
However, this doesn't work because vector<T>(int) is implemented in terms of default constructing an object and then copying it into each of the new locations.
不是 C++0xB(又名 C++11)
Not C++0xB (a.k.a. C++11)
推荐答案
一种选择是升级到符合 C++11 的标准库实现.
One option would be to upgrade to a C++11-compliant Standard Library implementation.
在 C++11 中，vector(size_type) 构造函数默认将 N 个元素构造到容器中.它既不复制也不移动任何元素.
In C++11, the vector(size_type) constructor default constructs N elements into the container. It neither copies nor moves any elements.
Visual C++ 2010 不支持这个 C++11 特性；我相信 Visual C++ 11 Developer Preview 确实正确支持它.我不知道最新版本的 libstdc++ 是否支持这个；我会怀疑 libc++ 会.
Visual C++ 2010 does not support this C++11 feature; I believe the Visual C++ 11 Developer Preview does correctly support it though. I do not know whether recent versions of libstdc++ support this; I would suspect that libc++ does.
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