nlohmann::basic_json::operator=¶

basic_json& operator=(basic_json other) noexcept (
    std::is_nothrow_move_constructible<value_t>::value &&
    std::is_nothrow_move_assignable<value_t>::value &&
    std::is_nothrow_move_constructible<json_value>::value &&
    std::is_nothrow_move_assignable<json_value>::value &&
    std::is_nothrow_move_assignable<json_base_class_t>::value
);

Copy assignment operator. Copies a JSON value via the "copy and swap" strategy: It is expressed in terms of the copy constructor, destructor, and the swap() member function.

Parameters¶

other (in): value to copy from

Exception safety¶

Strong guarantee: if an exception is thrown while copying other, there are no changes to *this.

Complexity¶

Linear.

Examples¶

Example

The code below shows and example for the copy assignment. It creates a copy of value a which is then swapped with b. Finally, the copy of a (which is the null value after the swap) is destroyed.

#include <iostream>
#include <nlohmann/json.hpp>

using json = nlohmann::json;

int main()
{
    // create JSON values
    json a = 23;
    json b = 42;

    // copy-assign a to b
    b = a;

    // serialize the JSON arrays
    std::cout << a << '\n';
    std::cout << b << '\n';
}

Output:

23
23

Version history¶

Added in version 1.0.0.