Re: Does object have function?

From:
"Amethy" <newskrq@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Fri, 29 Oct 2010 14:40:52 +0800
Message-ID:
<iadq91$388$1@www.shinco.com>
#include <iostream>
#include <string>
#include <cmath>
#include <fstream>
using namespace std;
class Base {
public:
   virtual ~Base() {}
};

class Fooer {
public:
   virtual void foo(){};
};

class DerivedOne : public Fooer {
public:
   void foo() { cout << "DerivedOne::foo()\n"; }
};

class DerivedTwo : public Fooer {
public:
   void foo() { cout << "DerivedTwo::foo()\n"; }
};

class DerivedThree: public Fooer{
};

int main() {
   Fooer* bps[3];
   bps[0] = new DerivedOne();
   bps[1] = new DerivedTwo();
   bps[2] = new DerivedThree();

   for ( int i = 0; i < 3; ++i ) {
      Fooer* thisOne = dynamic_cast<Fooer*>( bps[i] );
      if ( thisOne )
         thisOne->foo();
        else{
            cout<<"nothing"<<endl;
        }
   }
}
the result is
one
two

"Joshua Maurice" <joshuamaurice@gmail.com>
??????:2dbb59cb-2dde-44a0-a459-e6ebcd5f3cfd@g13g2000yqj.googlegroups.com...
On Oct 28, 6:02 pm, "Daniel T." <danie...@earthlink.net> wrote:

This would work:

class Base {
public:
virtual ~Base() {}

};

class Fooer {
public:
virtual void foo() = 0;

};

class DerivedOne : public Base, public Fooer {
public:
void foo() { cout << "DerivedOne::foo()\n"; }

};

class DerivedTwo : public Base, public Fooer {
public:
void foo() { cout << "DerivedTwo::foo()\n"; }

};

class DerivedThree: public Base {

};

int main() {
Base* bps[3];
bps[0] = new DerivedOne();
bps[1] = new DerivedTwo();
bps[2] = new DerivedThree();

for ( int i = 0; i < 3; ++i ) {
Fooer* thisOne = dynamic_cast<Fooer*>( bps[i] );
if ( thisOne )
thisOne->foo();
}

}


With this multiple inheritance design, I would guess that you probably
want to virtually inherit from Fooer as well (not done in the above
code).

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