[pornel]

reserve() reallocates by at least doubling the capacity.

reserve_exact() reallocates by exactly what you ask for.

If you reserve() space for 1 more element a 1000 times, you will get ~30 reallocations, not 1000.

This inexact nature is useful when the total size is unknown, but you append in batches. You could implement your own amortised growth strategy, but having one built-in makes it simple for different functions to cooperate.

[teo_zero]

> If you reserve() space for 1 more element a 1000 times, you will get ~30 reallocations, not 1000.

Surely you mean ~10 reallocations, because 2^10=1024, right?