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# basic_json::out_of_range

    class out_of_range : public exception;

This exception is thrown in case a library function is called on an input parameter that exceeds the expected range, for instance in case of array indices or nonexisting object keys.

Exceptions have ids 4xx.

## Member functions

- what - returns explanatory string

## Member variables

- id - the id of the exception

## Example

Example

The following code shows how a `out_of_range` exception can be caught.

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

    using json = nlohmann::json;

    int main()
    {
        try
        {
            // calling at() for an invalid index
            json j = {1, 2, 3, 4};
            j.at(4) = 10;
        }
        catch (json::out_of_range& e)
        {
            // output exception information
            std::cout << "message: " << e.what() << '\n'
                      << "exception id: " << e.id << std::endl;
        }
    }

Output:

    message: [json.exception.out_of_range.401] array index 4 is out of range
    exception id: 401

## Version history

- Since version 3.0.0.