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

From cppreference.com
< cpp‎ | container‎ | inplace vector

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.

### 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

### Complexity

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

### 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.

### Example

Run this code

    #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

### See also

(constructor) | constructs the `inplace_vector` (public member function)
assign | assigns values to the container (public member function)

Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/container/inplace_vector/operator%3D&oldid=175717"