Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.csd.uwm.edu!bionet!agate!ucbvax!hplabs!hp-pcd!hplsla!jima
From: jima@hplsla.HP.COM (Jim Adcock)
Newsgroups: comp.lang.c++
Subject: Re: Can't inherit abstract classes -> pain and suffering
Message-ID: <6590233@hplsla.HP.COM>
Date: 21 Aug 89 22:37:41 GMT
References: <1989Aug21.132230.17200@odi.com>
Organization: HP Lake Stevens, WA
Lines: 89

// try:

class base {
  public:
    int s;
    virtual int pred () = 0;
};

class mix {
  public:
    virtual int pred () {
	return 1;
    };
};

class mix0 {
  public:
    virtual int pred () {
	return 0;
    };
};

class top : public base, public mix 
{
  public:
    virtual int pred () {
	return (mix::pred());
    };
};

class top0 : public base, public mix0 {
  public:
    virtual int pred () {
	return (mix0::pred());
    };
};

int Q;

main ()
{
    top t;
    Q = t.pred();
}

// or try:

class base {
  public:
    int s;
    virtual int pred () = 0;
};

class mix {
  public:
    virtual int pred () {
	return 1;
    };
};

class mix0 {
  public:
    virtual int pred () {
	return 0;
    };
};

class top : public base, public mix 
{
  public:
    virtual int pred () {
	return ((mix*)(this))->pred();
    };
};

class top0 : public base, public mix0 {
  public:
    virtual int pred () {
	return ((mix0*)(this))->pred();
    };
};

int Q;

main ()
{
    top t;
    Q = t.pred();
}