我知道 std::vector
在内部连续地存储它的数据(除非它是 std::vector
),都在旧的 中>C++03
标准和新的C++11
.
I know that std::vector<T>
internally stores it's data contiguously (unless it is std::vector<bool>
) both in the old C++03
standard and the new C++11
.
处理这个问题并引用标准的不错的 stackoverflow 问题:answer、答案.
Nice stackoverflow questions that deal with this and quote the standard: answer, answer.
嵌套向量中的数据怎么样 std::vector
?它是如何存储的?
What about the data inside nested vectors std::vector <std::vector <T> >
? How is that stored?
如果每个内部向量都需要连续存储它的数据,那么 &v[n] == &v[0] + n for all 0 <= n
If every internal vector needs to store it's data contiguously, how can it be true that &v[n] == &v[0] + n for all 0 <= n < v.size()
.
用稍微不同的话说,是否可以简单地"并顺序地(通过指针或类似物)访问存储在这种嵌套结构中的所有元素一维向量?
To phrase this slightly different, is it possible to access all the elements stored in such nested structure "simply" and sequentially (via a pointer or similar) the same way it can be done for a 1-D vector?
没有.vector
的元素存储在动态分配的内存块中;否则,vector
的容量无法增加.vector
对象只包含一个指向该块的指针.
No. The elements of a vector
are stored in a dynamically allocated block of memory; otherwise, the capacity of the vector
could not increase. The vector
object just holds a pointer to that block.
元素顺序存储的要求仅适用于元素本身,而不适用于这些元素的任何动态分配的成员.
The requirement that the elements be stored sequentially applies only to the elements themselves, and not to any dynamically allocated members of those elements.
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