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Explicit Overrides (C++)

Microsoft Specific

If the same virtual function is declared in two or more interfaces and if a class is derived from these interfaces, you can explicitly override each virtual function.

For information on explicit overrides in managed code using the new managed syntax, see Explicit Overrides.

END Microsoft Specific

The following code example illustrates how to use explicit overrides:

// deriv_ExplicitOverrides.cpp
// compile with: /GR
extern "C" int printf_s(const char *, ...);

__interface IMyInt1 {
   void mf1();
   void mf1(int);
   void mf2();
   void mf2(int);
};

__interface IMyInt2 {
   void mf1();
   void mf1(int);
   void mf2();
   void mf2(int);
};

class CMyClass : public IMyInt1, public IMyInt2 {
public:
   void IMyInt1::mf1() {
      printf_s("In CMyClass::IMyInt1::mf1()\n");
   }

   void IMyInt1::mf1(int) {
      printf_s("In CMyClass::IMyInt1::mf1(int)\n");
   }

   void IMyInt1::mf2();
   void IMyInt1::mf2(int);

   void IMyInt2::mf1() {
      printf_s("In CMyClass::IMyInt2::mf1()\n");
   }

   void IMyInt2::mf1(int) {
         printf_s("In CMyClass::IMyInt2::mf1(int)\n");
   }

   void IMyInt2::mf2();
   void IMyInt2::mf2(int);
};

void CMyClass::IMyInt1::mf2() {
   printf_s("In CMyClass::IMyInt1::mf2()\n");
}

void CMyClass::IMyInt1::mf2(int) {
   printf_s("In CMyClass::IMyInt1::mf2(int)\n");
}

void CMyClass::IMyInt2::mf2() {
   printf_s("In CMyClass::IMyInt2::mf2()\n");
}

void CMyClass::IMyInt2::mf2(int) {
   printf_s("In CMyClass::IMyInt2::mf2(int)\n");
}

int main() {
   IMyInt1 *pIMyInt1 = new CMyClass();
   IMyInt2 *pIMyInt2 = dynamic_cast<IMyInt2 *>(pIMyInt1);

   pIMyInt1->mf1();
   pIMyInt1->mf1(1);
   pIMyInt1->mf2();
   pIMyInt1->mf2(2);
   pIMyInt2->mf1();
   pIMyInt2->mf1(3);
   pIMyInt2->mf2();
   pIMyInt2->mf2(4);

   // Cast to a CMyClass pointer so that the destructor gets called
      CMyClass *p = dynamic_cast<CMyClass *>(pIMyInt1);
      delete p;
}
In CMyClass::IMyInt1::mf1()
In CMyClass::IMyInt1::mf1(int)
In CMyClass::IMyInt1::mf2()
In CMyClass::IMyInt1::mf2(int)
In CMyClass::IMyInt2::mf1()
In CMyClass::IMyInt2::mf1(int)
In CMyClass::IMyInt2::mf2()
In CMyClass::IMyInt2::mf2(int)
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