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

 

C++

Compiler support

Freestanding and hosted

Language

Standard library

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Metaprogramming library (C++11)

Diagnostics library

General utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Localizations library

Input/output library

Filesystem library (C++17)

Regular expressions library (C++11)

Concurrency support library (C++11)

Execution support library (C++26)

Technical specifications

Symbols index

External libraries

 

Containers library

Sequence

array (C++11)

vector

vector<bool>

inplace_vector (C++26)

deque

forward_list (C++11)

list

Associative

set

multiset

map

multimap

Unordered associative

unordered_set (C++11)

unordered_multiset (C++11)

unordered_map (C++11)

unordered_multimap (C++11)

Adaptors

stack

queue

priority_queue

flat_set (C++23)

flat_multiset (C++23)

flat_map (C++23)

flat_multimap (C++23)

Views

span (C++20)

mdspan (C++23)

Tables

Iterator invalidation

Member function table

Non-member function table

 

std::inplace_vector

Member types
Member functions
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 assign( size_type count, const T& value );	(1)	(since C++26)
template< class InputIt > constexpr void assign( InputIt first, InputIt last );	(2)	(since C++26)
constexpr void assign( std::initializer_list<T> ilist );	(3)	(since C++26)

Replaces the contents of the container.

1) Replaces the contents with count copies of value value.

2) Replaces the contents with copies of those in the range [first, last). The behavior is undefined if either argument is an iterator into *this. This overload participates in overload resolution only if InputIt satisfies LegacyInputIterator.

3) Replaces the contents with the elements from the initializer list ilist.

Parameters

count	-	the new size of the container
value	-	the value to initialize elements of the container with
first, last	-	the range to copy the elements from
ilist	-	initializer list to copy the values from

Complexity

1) Linear in count.

2) Linear in distance between first and last.

3) Linear in ilist.size().

Exceptions

1) std::bad_alloc, if count > capacity().

2) std::bad_alloc, if std::ranges::distance(first, last) > capacity().

3) std::bad_alloc, if ilist.size() > capacity().

1-3) Any exception thrown by initialization of inserted elements.

Example

The following code uses assign to add several characters to a std::inplace_vector<char, 5>:

Run this code

#include <inplace_vector>
#include <iterator>
#include <new>
#include <print>
 
int main()
{
    std::inplace_vector<char, 5> chars;
 
    chars.assign(4, 'a'); // overload (1)
    std::println("{}", chars);
 
    const char extra[3]{'a', 'b', 'c'};
    chars.assign(std::cbegin(extra), std::cend(extra)); // overload (2)
    std::println("{}", chars);
 
    chars.assign({'C', '+', '+', '2', '6'}); // overload (3)
    std::println("{}", chars);
 
    try
    {
        chars.assign(8, 'x'); // throws: count > chars.capacity()
    }
    catch(const std::bad_alloc&) { std::println("std::bad_alloc #1"); }
 
    try
    {
        const char bad[8]{'?'}; // ranges::distance(bad) > chars.capacity()
        chars.assign(std::cbegin(bad), std::cend(bad)); // throws
    }
    catch(const std::bad_alloc&) { std::println("std::bad_alloc #2"); }
 
    try
    {
        const auto l = {'1', '2', '3', '4', '5', '6'};
        chars.assign(l); // throws: l.size() > chars.capacity()
    }
    catch(const std::bad_alloc&) { std::println("std::bad_alloc #3"); }
}

Output:

['a', 'a', 'a', 'a']
['a', 'b', 'c']
['C', '+', '+', '2', '6']
std::bad_alloc #1
std::bad_alloc #2
std::bad_alloc #3

See also

assign_range	assigns a range of values to the container (public member function)
operator=	assigns values to the container (public member function)