std::inplace_vector<T,N>::resize

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std::inplace_vector

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inplace_vector::inplace_vector inplace_vector::~inplace_vector    inplace_vector::operator= inplace_vector::assign inplace_vector::assign_range Size and capacity inplace_vector::empty inplace_vector::size inplace_vector::max_size inplace_vector::capacity inplace_vector::resize inplace_vector::reserve inplace_vector::shrink_to_fit Iterators inplace_vector::begininplace_vector::cbegin inplace_vector::endinplace_vector::cend inplace_vector::rbegininplace_vector::crbegin inplace_vector::rendinplace_vector::crend	Element access inplace_vector::at inplace_vector::operator[] inplace_vector::front inplace_vector::back inplace_vector::data Modifiers inplace_vector::clear inplace_vector::erase inplace_vector::swap inplace_vector::insert inplace_vector::insert_range inplace_vector::emplace inplace_vector::emplace_back inplace_vector::try_emplace_back inplace_vector::unchecked_emplace_back inplace_vector::push_back inplace_vector::try_push_back inplace_vector::unchecked_push_back inplace_vector::pop_back inplace_vector::append_range inplace_vector::try_append_range
Non-member functions
erase(std::inplace_vector)erase_if(std::inplace_vector) swap(std::inplace_vector)	operator==operator<=>

 

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

1,2) Throws std::bad_alloc if count > N.

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]

See also

max_size [static]	returns the maximum possible number of elements (public static member function)
size	returns the number of elements (public member function)
capacity [static]	returns the number of elements that can be held in currently allocated storage (public static member function)
empty	checks whether the container is empty (public member function)