[C++] Vector Changing Size allocator 、RAII 、 unique_ptr
VectorChangingsizeVectorChangingsizeordinaryreserve()voidvector::reserve(intnewalloc){if(newallocclassallocator{public://...T*allocate(intn);//allocatespacefornobjectsoftypeTvoiddeallocate(T*p,intn);/