C++ 로 Containment 구현하기

#include <objbase.h>

interface ICalcu : IUnknown
{
    virtual int __stdcall Sum(int x, int y) = 0;
    virtual int __stdcall Sub(int x, int y) = 0;
    virtual int __stdcall Mul(int x, int y) = 0;
    virtual double __stdcall Div(int x, int y) = 0;
};

interface IRadius : IUnknown
{
    virtual double __stdcall Radius(int x, int y) = 0;
};

HRESULT __stdcall CFactory::CreateInstance(IUnknown* pUnknownOuter,
                                           const IID& iid,
                                           void** ppv)
{
    if(pUnknownOuter != NULL)
    {
        return CLASS_E_NOAGGREGATION;
    }

    CSimpleCalc2* pSc = new CSimpleCalc2;
//    CSimpleCalc* pSc = new CSimpleCalc;
    if(pSc == NULL)
    {
        return E_OUTOFMEMORY;
    }

    HRESULT hr = pSc->InitContainment() ;
    if (FAILED(hr))
    {
        // Initialization failed. Delete component.
        pSc->Release() ;
        return hr ;
    }

    /* HRESULT */hr = pSc->QueryInterface(iid,ppv);

    pSc->Release();

    return hr;
}


#include "interface.h"

class CSimpleCalc2 : public IRadius 
{
public:
...
    // ICalcu
    virtual double        __stdcall Radius(int x, int y);

...
    HRESULT InitContainment() ;

private:
...

    ICalcu *m_pCal ;
};

#include <math.h>
...
CSimpleCalc2::~CSimpleCalc2()
{
    InterlockedDecrement(&g_cComponents);

    if (m_pCal != NULL)
    {
        m_pCal->Release() ;
    }
}

HRESULT CSimpleCalc2::InitContainment()
{
    HRESULT hr = ::CoCreateInstance(CLSID_COMPONENT,
                                    NULL,
                                    CLSCTX_INPROC_SERVER,
                                    IID_ICalcu,
                                    (void**)&m_pCal) ;
    if (FAILED(hr))
    {
        return E_FAIL ;
    }
    else
    {
        return S_OK ;
    }
}

double    __stdcall CSimpleCalc2::Radius(int x, int y)
{
    int x2, y2, z2;

    x2 = m_pCal->Mul(x,x);
    y2 = m_pCal->Mul(y,y);
    z2 = m_pCal->Sum(x2,y2);

    return sqrt(z2);
}