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std::inplace_vector<T,N>::operator=

From cppreference.com
 
 
 
 
constexpr inplace_vector& operator=( const inplace_vector& other );
(1) (since C++26)
constexpr inplace_vector& operator=( inplace_vector&& other )
    noexcept(/* see below */);
(2) (since C++26)
constexpr inplace_vector& operator=( std::initializer_list<T> init );
(3) (since C++26)

Replaces the contents of the inplace_vector.

1) Copy assignment operator. Also a trivial copy assignment operator, if std::inplace_vector<T, N> has a trivial destructor, and std::is_trivially_copy_constructible_v<T> && std::is_trivially_copy_assignable_v<T> is true. Replaces the contents with a copy of the contents of other.
2) Move assignment operator. Also a trivial move assignment operator, if std::inplace_vector<T, N> has a trivial destructor, and std::is_trivially_move_constructible_v<T> && std::is_trivially_move_assignable_v<T> is true. Replaces the contents with those of other using move semantics (i.e., the data in other is moved from other into this container). other is in a valid but unspecified state afterwards.
3) Replaces the contents with those identified by initializer list init.

Contents

[edit] Parameters

other - another inplace_vector to be used as source to initialize the elements of the container with
init - initializer list to initialize the elements of the container with

[edit] Complexity

1,2) Linear in the size of *this and other.
3) Linear in the size of *this and init.

[edit] Exceptions

2)
noexcept specification:  
noexcept(N == 0 ||

        (std::is_nothrow_move_assignable_v<T> &&

         std::is_nothrow_move_constructible_v<T>))
3) Throws std::bad_alloc if init.size() > N.

[edit] Example

#include <initializer_list>
#include <inplace_vector>
#include <new>
#include <print>
#include <ranges>
#include <string>
 
int main()
{
    std::inplace_vector<int, 4> x({1, 2, 3}), y;
    std::println("Initially:");
    std::println("x = {}", x);
    std::println("y = {}", y);
 
    std::println("Copy assignment copies data from x to y:");
    y = x; // overload (1)
    std::println("x = {}", x);
    std::println("y = {}", y);
 
    std::inplace_vector<std::string, 3> z, w{"\N{CAT}", "\N{GREEN HEART}"};
    std::println("Initially:");
    std::println("z = {}", z);
    std::println("w = {}", w);
 
    std::println("Move assignment moves data from w to z:");
    z = std::move(w); // overload (2)
    std::println("z = {}", z);
    std::println("w = {}", w); // w is in valid but unspecified state
 
    auto l = {4, 5, 6, 7};
    std::println("Assignment of initializer_list {} to x:", l);
    x = l; // overload (3)
    std::println("x = {}", x);
 
    std::println("Assignment of initializer_list with size bigger than N throws:");
    try
    {
        x = {1, 2, 3, 4, 5}; // throws: (initializer list size == 5) > (capacity N == 4)
    }
    catch(const std::bad_alloc& ex)
    {
        std::println("ex.what(): {}", ex.what());
    }
}

Possible output:

Initially:
x = [1, 2, 3]
y = []
Copy assignment copies data from x to y:
x = [1, 2, 3]
y = [1, 2, 3]
Initially:
z = []
w = ["🐈", "💚"]
Move assignment moves data from w to z:
z = ["🐈", "💚"]
w = ["", ""]
Assignment of initializer_list [4, 5, 6, 7] to x:
x = [4, 5, 6, 7]
Assignment of initializer_list with size bigger than N throws:
ex.what(): std::bad_alloc

[edit] See also

constructs the inplace_vector
(public member function) [edit]
assigns values to the container
(public member function) [edit]