std::inplace_vector<T,N>::resize
From cppreference.com
constexpr void resize( size_type count );
|
(1) | (since C++26) |
constexpr void resize( size_type count, const value_type& value );
|
(2) | (since C++26) |
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:
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).
| ||
Complexity
Linear in the difference between the current size and count.
Exceptions
If an exception is thrown for any reason, these functions have no effect (strong exception safety guarantee).
Example
Run this code
#include <inplace_vector>
#include <print>
int main()
{
std::inplace_vector<int, 6> v(6, 9);
std::println("Initially, v = {}", v);
v.resize(2);
std::println("After resize(2), v = {}", v);
v.resize(4);
std::println("After resize(4), v = {}", v);
v.resize(6, -1);
std::println("After resize(6, -1), v = {}", v);
try
{
std::print("Trying resize(13): ");
v.resize(13); // throws, because count > N; v is left unchanged
}
catch(const std::bad_alloc& ex)
{
std::println("ex.what(): {}", ex.what());
}
std::println("After exception, v = {}", v);
}
Possible output:
Initially, v = [9, 9, 9, 9, 9, 9]
After resize(2), v = [9, 9]
After resize(4), v = [9, 9, 0, 0]
After resize(6, -1), v = [9, 9, 0, 0, -1, -1]
Trying resize(13): ex.what(): std::bad_alloc
After exception, v = [9, 9, 0, 0, -1, -1]