[英]Should I reserve memory when using std::back_inserter
Do I need to reserve memory when using a back:inserter? 使用背部时是否需要保留内存:插入器?
d.reserve(s.size())
std::copy (s.begin(),s.end(),back_inserter(d));
You do not need to reserve memory for the container when using std::back_inserter
. 使用std::back_inserter
时,不需要为容器保留内存。 However, if you know beforehand about the number of elements you are going to insert and want to prevent repeated allocations you may reserve memory. 但是,如果您事先知道要插入的元素数量并希望防止重复分配,则可以保留内存。
You don't have to. 你不必。 However, if this code snippet is run very frequently, you may consider reserving memory to improve performance. 但是,如果此代码段运行频繁,您可以考虑保留内存以提高性能。
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