std::vector::shrink_to_fit

 

C++

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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.

Parameters

(none)

Return value

(none)

Complexity

Constant

Example

#include <iostream>
#include <vector>
int main()
{
    std::vector<int> v;
    std::cout << "Default-constructd 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';
}

Output:

Default-constructd capacity is 0
Capacity of a 100-element vector is 100
Capacity after clear() is 100
Capacity after shrink_to_fit() is 0

See also

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