std::inplace_vector<T,N>::assign - cppreference.com (original) (raw)
| 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.
Replaces the contents with count copies of value value.
Replaces the contents with copies of those in the range
[first,last).
This overload participates in overload resolution only if InputIt satisfies the requirements of LegacyInputIterator.
If first or last is an iterator into *this, the behavior is undefined.
- Replaces the contents with the elements from ilist.
[edit] 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 | - | std::initializer_list to copy the values from |
[edit] Complexity
Linear in count.
Linear in distance between first and last.
Linear in ilist.size().
Exceptions
1-3) Any exception thrown by initialization of inserted elements.
[edit] Example
The following code uses assign to add several characters to a std::inplace_vector<char, 5>:
#include #include #include #include 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