C++ Primer, Fifth Edition

StrVec Class Design

Recall that the vector class stores its elements in contiguous storage. To obtain acceptable performance, vector preallocates enough storage to hold more elements than are needed (§ 9.4, p. 355). Each vector member that adds elements checks whether there is space available for another element. If so, the member constructs an object in the next available spot. If there isn’t space left, then the vector is reallocated: The vector obtains new space, moves the existing elements into that space, frees the old space, and adds the new element.

We’ll use a similar strategy in our StrVec class. We’ll use an allocator to obtain raw memory (§ 12.2.2, p. 481). Because the memory an allocator allocates is unconstructed, we’ll use the ...