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c++stddynamic-cast

'bad_cast' in namespace 'std' does not name a type Error

given the next code: 

#include <iostream>
using std::cout;
using std::endl;
using std::cerr;

class A {
public:
    virtual ~A() {
    }
};

class B: public A {
public:

};

int main() {
    int n = 4;
    A a;
    A& base = a;
    B* ptr = dynamic_cast<B*>(&base);
    if (ptr == NULL) {
        cerr << "base is not a B";
    }
    try {
        B& derived = dynamic_cast<B&>(base);
        derived = *ptr;
    } catch (std::bad_cast&) { // ERROR
        cerr << "base is not a B";
    }
    if (n == 3) {
    }
    return 0;
}

I get this message error and I don't understand what is the reason and how can I fix it?

'bad_cast' in namespace 'std' does not name a type

Solution

  • If you look up the documentation at http://en.cppreference.com/w/cpp/types/bad_cast it tells you at the top which include is required for each class/function. In this case you need to include <typeinfo>