C / C++ / MFC

#include "stdafx.h"

class B
{};

class D : public B
{};

int _tmain(int argc, _TCHAR* argv[])
{
    try 
    {
        B* p = new D;
        throw p;
    }
    catch (D* ex)
    {
        delete ex;
        printf("catch (D* ex)\n");
    }
    catch (B* ex)
    {
        delete ex;
        printf("catch (B* ex)\n");
    }

    return 0;
}

class Operation
{
public:
	Operation() { m_DurationCalculated=false;} ;
	~Operation();

	long getDuration()
	{
		computeDuration();
		return m_Duration;
	};

private:
	long m_Duration;
	bool m_DurationCalculated;

	void computeDuration()
	{
		if (!m_DurationCalculated)
		{
			// ...
			// Compute duration
			// ...
			m_Duration=/*...*/;
			m_DurationCalculated=true;
		}
	}
};

#ifndef CREATE_STATIC
	IMPLEMENT_DYNCREATE(CMyOwnViewCls, CWnd)
#endif