---
title: "bad_cast Exception"
ms.date: "11/04/2016"
f1_keywords: ["bad_cast", "bad_cast_cpp"]
helpviewer_keywords: ["exceptions [C++], bad_cast", "bad_cast keyword [C++]"]
ms.assetid: 31eae1e7-d8d5-40a0-9fef-64a6a4fc9021
---
# bad_cast Exception

The **bad_cast** exception is thrown by the **dynamic_cast** operator as the result of a failed cast to a reference type.

## Syntax

```
catch (bad_cast)
   statement
```

## Remarks

The interface for **bad_cast** is:

```cpp
class bad_cast : public exception {
public:
   bad_cast(const char * _Message = "bad cast");
   bad_cast(const bad_cast &);
   virtual ~bad_cast();
};
```

The following code contains an example of a failed **dynamic_cast** that throws the **bad_cast** exception.

```cpp
// expre_bad_cast_Exception.cpp
// compile with: /EHsc /GR
#include <typeinfo.h>
#include <iostream>

class Shape {
public:
   virtual void virtualfunc() const {}
};

class Circle: public Shape {
public:
   virtual void virtualfunc() const {}
};

using namespace std;
int main() {
   Shape shape_instance;
   Shape& ref_shape = shape_instance;
   try {
      Circle& ref_circle = dynamic_cast<Circle&>(ref_shape);
   }
   catch (bad_cast b) {
      cout << "Caught: " << b.what();
   }
}
```

The exception is thrown because the object being cast (a Shape) is not derived from the specified cast type (Circle). To avoid the exception, add these declarations to `main`:

```cpp
Circle circle_instance;
Circle& ref_circle = circle_instance;
```

Then reverse the sense of the cast in the **try** block as follows:

```cpp
Shape& ref_shape = dynamic_cast<Shape&>(ref_circle);
```

## See also

[dynamic_cast Operator](../cpp/dynamic-cast-operator.md)<br/>
[Keywords](../cpp/keywords-cpp.md)<br/>
[C++ Exception Handling](../cpp/cpp-exception-handling.md)