interfaces.cpp

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//: C09:Interfaces.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.
// Multiple interface inheritance.
#include <iostream>
#include <sstream>
#include <string>
using namespace std;

class Printable {
public:
  virtual ~Printable() {}
  virtual void print(ostream&) const = 0;
};

class Intable {
public:
  virtual ~Intable() {}
  virtual int toInt() const = 0;
};

class Stringable {
public:
  virtual ~Stringable() {}
  virtual string toString() const = 0;
};

class Able : public Printable, public Intable,
             public Stringable {
  int myData;
public:
  Able(int x) { myData = x; }
  void print(ostream& os) const { os << myData; }
  int toInt() const { return myData; }
  string toString() const {
    ostringstream os;
    os << myData;
    return os.str();
  }
};

void testPrintable(const Printable& p) {
  p.print(cout);
  cout << endl;
}

void testIntable(const Intable& n) {
  cout << n.toInt() + 1 << endl;
}

void testStringable(const Stringable& s) {
  cout << s.toString() + "th" << endl;
}

int main() {
  Able a(7);
  testPrintable(a);
  testIntable(a);
  testStringable(a);
} ///:~