# std::swap<basic_json\>

```cpp
namespace std {
    void swap(nlohmann::basic_json& j1, nlohmann::basic_json& j2);
}
```

Exchanges the values of two JSON objects.

## Parameters

`j1` (in, out)
:   value to be replaced by `j2`

`j2` (in, out)
:   value to be replaced by `j1`

## Exception safety

No-throw guarantee: this function never throws exceptions.

## Complexity

Constant.

## Possible implementation

```cpp
void swap(nlohmann::basic_json& j1, nlohmann::basic_json& j2)
{
    j1.swap(j2);
}
```

## Examples

??? example

    The following code shows how two values are swapped with `std::swap`.
     
    ```cpp
    #include <iostream>
    #include <iomanip>
    #include <nlohmann/json.hpp>
    
    using json = nlohmann::json;
    
    int main()
    {
        // create JSON values
        json j1 = {{"one", 1}, {"two", 2}};
        json j2 = {1, 2, 4, 8, 16};
    
        std::cout << "j1 = " << j1 << " | j2 = " << j2 << '\n';
    
        // swap values
        std::swap(j1, j2);
    
        std::cout << "j1 = " << j1 << " | j2 = " << j2 << std::endl;
    }
    
    ```
    
    Output:
    
    ```json
    j1 = {"one":1,"two":2} | j2 = [1,2,4,8,16]
    j1 = [1,2,4,8,16] | j2 = {"one":1,"two":2}
    
    ```

## See also

- [swap](swap.md)

## Version history

- Added in version 1.0.0.
- Extended for arbitrary basic_json types in version 3.10.5.