9.42.txt

Exercise 9.42: Given that you want to read a character at a time into a string,
and you know that you need to read at least 100 characters, how might you
improve the performance of your program?

We can define an empty string and use the reserve operation to set its capacity
to 100 or more. This will reduce the number of reallocation of the string for
the known minimum (or more) amount of character we expect to read. We could
also use a simple algorithm to request more memory than what we need initially,
and doubling the current capacity on each subsequent reallocations.
Furthermore, we could experiment with emplace_back operation to see if it gives
us improved performance over push_back--remember that emplace_back does not
push a COPY of the elements into the string but rather constructs them in the
string directly.