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#include <iostream>

using namespace std;

class AbstractClass
{
protected:
  virtual void AbstractFunc() = 0;
public:
  AbstractClass();
};

AbstractClass::AbstractClass()
{
  AbstractFunc();
}

int main()
{
  return 0;
}

In constructor 'AbstractClass::AbstractClass()':
warning: abstract virtual 'virtual void AbstractClass::AbstractFunc()' called from constructor
undefined reference to `AbstractClass::AbstractFunc()'
undefined reference to `AbstractClass::AbstractFunc()'
collect2: ld returned 1 exit status

class AbstractClass
{
protected:
  virtual void AbstractFunc() { cout << "AbstractClass" << endl; }
public:
  AbstractClass();
};

class RealClass: public AbstractClass
{
protected:
  void AbstractFunc() { cout << "RealClass\n" << endl; }
};

AbstractClass::AbstractClass()
{
  AbstractFunc();
}

int main()
{
  RealClass rc;
  return 0;
}

#include <iostream>

using namespace std;

class AbstractClass
{
public:
  virtual void AbstractFunc() = 0;
};
template <class TChild> AbstractClass* AbstractClass_Create(AbstractClass *instance)
{
  TChild* result = (TChild*)instance;
  result->AbstractFunc();
  return result;
}
AbstractClass* AbstractClass_Create(AbstractClass *instance);

class RealClass01: public AbstractClass
{
friend AbstractClass* AbstractClass_Create<RealClass01>(AbstractClass *instance);
protected:
  void AbstractFunc() { cout << "RealClass01" << endl; }
  virtual void RealFunc() = 0;
};
template <class TChild> RealClass01* RealClass01_Create(RealClass01 *instance)
{
  TChild* result = (TChild*)AbstractClass_Create<RealClass01>(instance);
  result->RealFunc();
  return result;
}
RealClass01* RealClass01_Create(RealClass01 *instance);

class FactClass01: public RealClass01
{
friend RealClass01* RealClass01_Create<FactClass01>(RealClass01 *instance);
protected:
  void RealFunc() { cout << "FactClass01" << endl; }
};

class RealClass02: public AbstractClass
{
friend AbstractClass* AbstractClass_Create<RealClass02>(AbstractClass *instance);
protected:
  void AbstractFunc() { cout << "RealClass02" << endl; }
};

int main()
{
  AbstractClass *fc_01 = RealClass01_Create<FactClass01>(new FactClass01);
  AbstractClass *rc_02 = AbstractClass_Create<RealClass02>(new RealClass02);
  delete fc_01;
  delete rc_02;
  return 0;
}

RealClass01
FactClass01
RealClass02

AbstractClass *rc_01 = AbstractClass_Create<RealClass01>(new RealClass01);
AbstractClass *rc_02 = AbstractClass_Create<RealClass02>(new RealClass02);

{
    AbstractDialog  *pDialog = createDialog("testName");
    if(pDialog->initFunc()) //это виртуальный метод.
        pDialog->exec(); //в конструкторе флаг DeleteOnClose
    else
        delete pDialog;
}