NAME

std::list::resize - std::list::resize

Synopsis

void resize( size_type count ); (1) (since C++11)
void resize( size_type count, T value = T() ); (until C++11)
void resize( size_type count, const value_type& (2) (since C++11)
value );

Resizes the container to contain count elements.

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,

1) additional default-inserted elements are appended
2) additional copies of value are appended.

Parameters

count - new size of the container
value - the value to initialize the new elements with

Type requirements

-
T must meet the requirements of DefaultInsertable in order to use overload (1).
-
T must meet the requirements of CopyInsertable in order to use overload (2).

Return value

(none)

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.

Example

// Run this code

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

Output:

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