Question

Consider this:

#include <iostream>
using namespace std;
class A{
   protected:
       void some_function(int params)
       {
        //inside A: do something A related 
       }
};

class B: public A{
public:
    void call_some_function(int params)
    {
    some_function(params); // Simple call to A::some_function and NOTHING MORE.
    }
};


int main(int argc, char *argv[])
{
   A* a = new A();

   ((B*)(a))->call_some_function(20); // Is it OK ?
}

This code works
What is the danger of using it ?

Answer 1

One danger is that call_some_function can only call functions (or access members in general) in A. All access to a member of B will result in access outside of allocated memory, with probably disastrous consequences.