Difference between revisions of "cpp/container/list/resize"

Latest revision as of 08:26, 15 September 2022

Resizes the container to contain count elements, does nothing if count == size().

If the current size is greater than count, the container is reduced to its first count elements.

If the current size is less than count, then:

[edit] Parameters

[edit] Complexity

Linear in the difference between the current size and count.

Notes

If value-initialization in overload (1) is undesirable, for example, if the elements are of non-class type and zeroing out is not needed, it can be avoided by providing a custom Allocator::construct.

[edit] Example

#include <list>
#include <iostream>
 
void print(auto rem, const std::list<int>& c)
{
    for (std::cout << rem; const int el : c)
        std::cout << el << ' ';
    std::cout << '\n';
}
 
int main()
{
    std::list<int> c = {1, 2, 3};
    print("The list holds: ", c);
 
    c.resize(5);
    print("After resize up to 5: ", c);
 
    c.resize(2);
    print("After resize down to 2: ", c);
 
    c.resize(6, 4);
    print("After resize up to 6 (initializer = 4): ", c);
}

The list holds: 1 2 3
After resize up to 5: 1 2 3 0 0
After resize down to 2: 1 2
After resize up to 6 (initializer = 4): 1 2 4 4 4 4

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

[edit] See also