virtinit.cpp

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//: C09:VirtInit.cpp
// From "Thinking in C++, Volume 2", by Bruce Eckel & Chuck Allison.
// (c) 1995-2004 MindView, Inc. All Rights Reserved.
// See source code use permissions stated in the file 'License.txt',
// distributed with the code package available at www.MindView.net.
// Illustrates initialization order with virtual bases.
#include <iostream>
#include <string>
using namespace std;

class M {
public:
  M(const string& s) { cout << "M " << s << endl; }
};

class A {
  M m;
public:
  A(const string& s) : m("in A") {
    cout << "A " << s << endl;
  }
  virtual ~A() {}
};

class B {
  M m;
public:
  B(const string& s) : m("in B")  {
    cout << "B " << s << endl;
  }
  virtual ~B() {}
};

class C {
  M m;
public:
  C(const string& s) : m("in C")  {
    cout << "C " << s << endl;
  }
  virtual ~C() {}
};

class D {
  M m;
public:
  D(const string& s) : m("in D") {
    cout << "D " << s << endl;
  }
  virtual ~D() {}
};

class E : public A, virtual public B, virtual public C {
  M m;
public:
  E(const string& s) : A("from E"), B("from E"),
  C("from E"), m("in E") {
    cout << "E " << s << endl;
  }
};

class F : virtual public B, virtual public C, public D {
  M m;
public:
  F(const string& s) : B("from F"), C("from F"),
  D("from F"), m("in F") {
    cout << "F " << s << endl;
  }
};

class G : public E, public F {
  M m;
public:
  G(const string& s) : B("from G"), C("from G"),
  E("from G"),  F("from G"), m("in G") {
    cout << "G " << s << endl;
  }
};

int main() {
  G g("from main");
} ///:~