memory management - C++ vector reduce allocation size -

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when c++ vector dynamically reduce allocated size in practice.

i know allocated space doubles upon insert full vector, it's not clear me when allocation reduced. classical hysteresis halve allocation size upon removal 1/4-full vector.

it never shrink allocated memory in absence of explicit direction so.

in c++11 there shrink_to_fit call ask implementation this, may not reduce allocated memory. in prior versions have create new copy , swap away old one.


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