// Listing 14.10
// Deriving ADTs from other ADTs
Code:
#include <iostream>
using namespace std;
enum COLOR { Red, Green, Blue, Yellow, White, Black, Brown } ;
class Animal // common base to both Mammal and Fish
{
public:
Animal(int);
virtual ~Animal() { cout << "Animal destructor...\n"; }
virtual int GetAge() const { return itsAge; }
virtual void SetAge(int age) { itsAge = age; }
virtual void Sleep() const = 0;
virtual void Eat() const = 0;
virtual void Reproduce() const = 0;
virtual void Move() const = 0;
virtual void Speak() const = 0;
private:
int itsAge;
};
Animal::Animal(int age):
itsAge(age)
{
cout << "Animal constructor...\n";
}
class Mammal : public Animal
{
public:
Mammal(int age):Animal(age)
{ cout << "Mammal constructor...\n";}
virtual ~Mammal() { cout << "Mammal destructor...\n";}
virtual void Reproduce() const
{ cout << "Mammal reproduction depicted...\n"; }
};
class Fish : public Animal
{
public:
Fish(int age):Animal(age)
{ cout << "Fish constructor...\n";}
virtual ~Fish() {cout << "Fish destructor...\n"; }
virtual void Sleep() const { cout << "fish snoring...\n"; }
virtual void Eat() const { cout << "fish feeding...\n"; }
virtual void Reproduce() const
{ cout << "fish laying eggs...\n"; }
virtual void Move() const
{ cout << "fish swimming...\n"; }
virtual void Speak() const { }
};
class Horse : public Mammal
{
public:
Horse(int age, COLOR color ):
Mammal(age), itsColor(color)
{ cout << "Horse constructor...\n"; }
virtual ~Horse() { cout << "Horse destructor...\n"; }
virtual void Speak()const { cout << "Whinny!... \n"; }
virtual COLOR GetItsColor() const { return itsColor; }
virtual void Sleep() const
{ cout << "Horse snoring...\n"; }
virtual void Eat() const { cout << "Horse feeding...\n"; }
virtual void Move() const { cout << "Horse running...\n";}
protected:
COLOR itsColor;
};
class Dog : public Mammal
{
public:
Dog(int age, COLOR color ):
Mammal(age), itsColor(color)
{ cout << "Dog constructor...\n"; }
virtual ~Dog() { cout << "Dog destructor...\n"; }
virtual void Speak()const { cout << "Whoof!... \n"; }
virtual void Sleep() const { cout << "Dog snoring...\n"; }
virtual void Eat() const { cout << "Dog eating...\n"; }
virtual void Move() const { cout << "Dog running...\n"; }
virtual void Reproduce() const
{ cout << "Dogs reproducing...\n"; }
protected:
COLOR itsColor;
};
int main()
{
Animal *pAnimal=0;
int choice;
bool fQuit = false;
while (1)
{
cout << "(1)Dog (2)Horse (3)Fish (0)Quit: ";
cin >> choice;
switch (choice)
{
case 1: pAnimal = new Dog(5,Brown);
break;
case 2: pAnimal = new Horse(4,Black);
break;
case 3: pAnimal = new Fish (5);
break;
default: fQuit = true;
break;
}
if (fQuit)
break;
pAnimal->Speak();
pAnimal->Eat();
pAnimal->Reproduce();
pAnimal->Move();
pAnimal->Sleep();
delete pAnimal;
cout << "\n";
}
return 0;
}
/*######################################*/
I have a question, because even though Mammal doesn't have a lot of method defined, I want to know if it still has this methods
virtual int GetAge() const { return itsAge; }
virtual void SetAge(int age) { itsAge = age; }
virtual void Sleep() const = 0;
virtual void Eat() const = 0;
virtual void Move() const = 0;
virtual void Speak() const = 0;
because it derives from Animal and therefore making it and ADT, so in turn you cannot make an instance of it? Is this right? If not please explain.