# nlohmann::basic_json::type_error
```cpp
class type_error : public exception;
```
This exception is thrown in case of a type error; that is, a library function is executed on a JSON value whose type
does not match the expected semantics.
Exceptions have ids 3xx (see [list of type errors](../../home/exceptions.md#type-errors)).
```mermaid
classDiagram
direction LR
class std_exception ["std::exception"] {
<>
}
class json_exception ["basic_json::exception"] {
+const int id
+const char* what() const
}
class json_parse_error ["basic_json::parse_error"] {
+const std::size_t byte
}
class json_invalid_iterator ["basic_json::invalid_iterator"]
class json_type_error ["basic_json::type_error"]
class json_out_of_range ["basic_json::out_of_range"]
class json_other_error ["basic_json::other_error"]
std_exception <|-- json_exception
json_exception <|-- json_parse_error
json_exception <|-- json_invalid_iterator
json_exception <|-- json_type_error
json_exception <|-- json_out_of_range
json_exception <|-- json_other_error
style json_type_error fill:#CCCCFF
```
## Member functions
- **what** - returns explanatory string
## Member variables
- **id** - the id of the exception
## Examples
??? example
The following code shows how a `type_error` exception can be caught.
```cpp
--8<-- "examples/type_error.cpp"
```
Output:
```json
--8<-- "examples/type_error.output"
```
## See also
- [List of type errors](../../home/exceptions.md#type-errors)
- [`parse_error`](parse_error.md) for exceptions indicating a parse error
- [`invalid_iterator`](invalid_iterator.md) for exceptions indicating errors with iterators
- [`out_of_range`](out_of_range.md) for exceptions indicating access out of the defined range
- [`other_error`](other_error.md) for exceptions indicating other library errors
## Version history
- Since version 3.0.0.