///////////////////////

class A
{
public:
  int a;
};

///////////////////////

class B : public A {};

///////////////////////

class C
{
public:
  virtual void c(A *a) = 0;
};

///////////////////////

class D : public C
{
  void c(B *b) {}
};

    # Exponent and modulus must be in a string in OpenSSL's MPINT

>>> from ctypes import create_string_buffer
>>> from struct import pack_into
>>> test = create_string_buffer(1)
>>> pack_into("B", test, 0, 48)
>>> print repr(test.raw)
'0'

>>> class A:
...  x = 1
...  y = 2
...  z = 3

#include <fstream>
using std::ofstream;
using std::endl;

ofstream fileStream("file.txt");
if (fileStream.good() == true) {
  fileStream << "This is a test message!" << endl;
  fileStream.close();
}