void shrink_to_fit(); | (since C++11) |
Requests the removal of unused capacity.
It is a non-binding request to reduce capacity()
to size()
. It depends on the implementation whether the request is fulfilled.
If reallocation occurs, all iterators, including the past the end iterator, and all references to the elements are invalidated. If no reallocation takes place, no iterators or references are invalidated.
(none).
Type requirements | ||
-T must meet the requirements of MoveInsertable. |
(none).
At most linear in the size of the container.
If an exception is thrown other than by T's move constructor, there are no effects.
#include <iostream> #include <vector> int main() { std::vector<int> v; std::cout << "Default-constructed capacity is " << v.capacity() << '\n'; v.resize(100); std::cout << "Capacity of a 100-element vector is " << v.capacity() << '\n'; v.clear(); std::cout << "Capacity after clear() is " << v.capacity() << '\n'; v.shrink_to_fit(); std::cout << "Capacity after shrink_to_fit() is " << v.capacity() << '\n'; }
Possible output:
Default-constructed capacity is 0 Capacity of a 100-element vector is 100 Capacity after clear() is 100 Capacity after shrink_to_fit() is 0
returns the number of elements (public member function) |
|
returns the number of elements that can be held in currently allocated storage (public member function) |
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