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

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).

If either argument is an iterator into *this, the behavior is undefined.
This overload participates in overload resolution only if InputIt satisfies LegacyInputIterator.

Each iterator in the range [first, last) is dereferenced exactly once.

3) Replaces the contents with the elements from ilist.

Parameters

count	-	the new size of the container
value	-	the value to initialize elements of the container with
first, last	-	the pair of iterators defining the source range of elements to copy
ilist	-	the 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>:

#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

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

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

Parameters

Complexity

Exceptions

Example

See also