STL General - How to clear extra capacity of vector?

Q: How to clear extra capacity of vector?

A: Use the shrink-to-fit technique.

Code:

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std::vector<int> myvector;
myvector.reserve(10000);
//use vector
//don't need extra capacity?
//clear it using shrink-to-fit technique:
std::vector<int>(myvector).swap(myvector);

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If you want to clear it all (no elements required but the vector lives because of scope), do this:

Code:

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std::vector<int>().swap(myvector);

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For more information on this please refer the following link:

• Using vector and deque by Herb Sutter (GotW #54)
• Item 17: Use "the swap trick" to trim excess capacity by Scott Meyers (Effective STL, Item 17)