< cpp‎ | container‎ | vector

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 if the request is fulfilled.

All iterators, including the past the end iterator, are potentially invalidated.


[edit] Parameters


Type requirements
T must meet the requirements of MoveInsertable.

[edit] Return value


[edit] Complexity

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.

[edit] Example

#include <iostream>
#include <vector>
int main()
    std::vector<int> v;
    std::cout << "Default-constructed capacity is " << v.capacity() << '\n';
    std::cout << "Capacity of a 100-element vector is " << v.capacity() << '\n';
    std::cout << "Capacity after clear() is " << v.capacity() << '\n';
    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

[edit] See also

returns the number of elements
(public member function)
returns the number of elements that can be held in currently allocated storage
(public member function)