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Chapter6

6.1.1

Image 1:

This image shows a picture of two diagrams defining a subclass. These have been written out below.

Single Inheritance: This diagram shows a large square orange box called SuperClass. There is a smaller blue box called SubClass positioned below the SuperClass box with an arrow pointing towards the SuperClass box.

Multiple Inheritance: This diagram shows two large square orange boxes called SuperClassA and SuperClassB. There is a smaller blue box called SubClass positioned below the SuperClassA and SuperClassB boxes with an arrow pointing towards the SuperClassA and SuperClassB boxes.

6.1.2

Image 1:

This image shows an example of defining a subclass in C++. The example code is written out below.

#include <iostream>
using namespace std;
class Super {
private:
	int storage;
public: 
	void put(int val) {storage = val; }
	int get(void) {return storage; }
};
int main(void) {
	Super object;
	object.put(100);
	object.put(object.get() + 1);
	cout<<object.get()<<endl;
	return 0;
}

6.1.3

Image 1:

This image shows another example of defining a subclass. The code is written out below.

class Y : {visibility specifier} X {....};

6.1.4

Image 1:

This image shows another example of defining a subclass. The code is written out below.

class Sub: Super {
};

int main(void) {
	Sub object;

	object.put(100);
	object.put(object.get() + 1);
	cout<<object.get()<<endl;
	return 0;
}

6.1.5

Image 1:

This image shows another example of defing a simple subclass. The code is written out below.

#include <iostream>

using namespace std;

class Super {
private:
	int storage;
public: 
	void put(int val) {storage = val; }
	int get(void) {return storage; }
};

class Sub : public Super {
};

int main(void) {
	Sub object;

	object.put(100);
	object.put(object.get() + 1);
	cout<<object.get()<<endl;
	return 0;
}

6.1.6

Image 1:

This image shows another example of defining a sub class. The code is written out below.

#include <iostream>

using namespace std;

class Super {
protected:
	int storage;
public: 
	void put(int val) {storage = val; }
	int get(void) {return storage; }
};

class Sub : public Super {
public:
	void print(void) {cout<<”storage = ”<<storage<<endl; }
};

int main(void) {
	Sub object;

	object.put(100);
	object.put(object.get() + 1);
	object.print();
	return 0;
}

6.1.7

Image 1:

This image shows a table used for defining sub classes. The table has been written out below.

When the component is declared as:	When the class is inherited as:	The resulting access inside the subclass is:
Public	Public	Public
Protected		Protected
Private		None
Public	Protected	Protected
Protected		Protected
Private		None
Public	Private	Private
Protected		Private
Private		None

6.1.8

Image 1:

This image shows another example of defining a subclass. The code is written out below.

#include <iostream>
using namespace std;
class SuperA {
protected:
	int storage;
public: 
	void put(int val) {storage = val; }
	int get(void) {return storage; }
};
class SuperB {
protected:
	int safe;
public:
	void insert(int val) {safe = val; }
	int takeout(void) {return safe; }
};
class Sub : public SuperA, public SuperB {
public: 
	void print(void) {
		cout<<”storage = “<<storage<<endl;
		cout<<”Safe  =”<<safe<<endl;
	}
};
int main(void) {
	sub object;
object.put(1);	object.insert(2);
object.put(object.get() + object.takeout());
object.insert(object.get() + object.takeout());
object.print();
return 0;
}

6.2.1

Image 1:

This image shows an example of simple type compatibility in C++. The example code is written out below.

#include <iostream>
using namespace std;
class Cat {
public: 
	void MakeSound(void) {cout<<”Meow! Meow!”<<endl; }
};
class Dog {
public:
	 void MakeSound(void) {cout<<”Woof! Woof!”<<endl; }
};
int main(void) {
	Cat *a_cat = new Cat();
	Dog *a_dog = new dog();  
	a_cat -> MakeSound();
	a_dog -> MakeSound();
	return 0;
}

6.2.2

Image 1:

This image shows an example of a more complex case of type compatibility. The code is written out below.

#include <iostream>
#include <string>
using namespace std;
class Pet {
protected:
	string Name;
public:
	Pet(string n) {Name = n; }
	void Run(void) {cout<<Name<<”: i’m running”<<endl; }
};
class Dog : public Pet {
public:
	Dog(string n) : Pet(n) {};
	void MakeSound(void) {cout<<Name<<”: Woof! Woof!”<<endl; }
};
class Cat : public Pet {
public:
	Cat(string n) : Pet(n) {};
	void MakeSound(void) {cout<<Name<<”: Meow! Meow!”<<endl; }
};
int main(void) {
	Pet a_pet(“pet”);
	Cat a_cat(“Tom”);
	Dog a_dog(“Spike”);
	A_pet.Run();
	A_dog.Run(); a_dog.MakeSound();
	A_cat.Run(); a_cat.MakeSound();
	Return 0;
}

6.2.3

Image 1:

This image shows another example of a complex case of type compatibility written out below.

#include <iostream>
#include <string>
using namespace std;
class Pet {
protected:
	string Name;
public:
	Pet(string n) {Name = n; }
	void Run(void) {cout<<Name<<”: i’m running”<<endl; }
};
class Dog : public Pet {
public:
	Dog(string n) : Pet(n) {};
	void MakeSound(void) {cout<<Name<<”: Woof! Woof!”<<endl; }
};
class Cat : public Pet {
public:
	Cat(string n) : Pet(n) {};
	void MakeSound(void) {cout<<Name<<”: Meow! Meow!”<<endl; }
};
int main(void) {
Pet *a_pet1 = new Cat(“Tom”);
Pet *a_pet1 = new Dog(“Spike”);

a_pet1 -> Run();
// ‘a_pet1 -> Makesound(); ‘is not allowed here!
a_pet2 -> Run();
// ‘a_pet2 -> Makesound(); ‘is not allowed here!

return 0;
}

6.2.4

Image 1:

This image shows an example of the static cast operator in C++. The code is written out below.

Static_cast<target_type>(an_expression)

6.2.5

Image 1:

This image shows an example of type compatibility, this time with static cast operators included. The code has been written out below.

#include <iostream>
#include <string>
using namespace std;
class Pet {
protected:
string Name;
public:
Pet(string n) {Name = n; }
void Run(void) {cout<<Name<<”: i’m running”<<endl; }
};
class Dog : public Pet {
public:
Dog(string n) : Pet(n) {};
void MakeSound(void) {cout<<Name<<”: Woof! Woof!”<<endl; }
};
class Cat : public Pet {
public:
Cat(string n) : Pet(n) {};
void MakeSound(void) {cout<<Name<<”: Meow! Meow!”<<endl; }
};
int main(void) {
Pet *a_pet1 = new Cat(“Tom”);
Pet *a_pet1 = new Dog(“Spike”);
a_pet1 -> Run();
static_cast<Cat *>(a_pet1) -> MakeSound();
a_pet2 -> Run();
static_cast<Dog *>(a_pet2) -> MakeSound();
return 0;
};

6.2.6

Image 1:

This image shows another example of type compatability with static cast operators. However this time the static cast operator has been abused. The code has been written out below.

#include <iostream>
#include <string>
using namespace std;
class Pet {
protected:
string Name;
public:
Pet(string n) {Name = n; }
void Run(void) {cout<<Name<<”: i’m running”<<endl; }
};
class Dog : public Pet {
public:
Dog(string n) : Pet(n) {};
void MakeSound(void) {cout<<Name<<”: Woof! Woof!”<<endl; }
};
class Cat : public Pet {
public:
Cat(string n) : Pet(n) {};
void MakeSound(void) {cout<<Name<<”: Meow! Meow!”<<endl; }
};
int main(void) {
Pet *a_pet1 = new Cat(“Tom”);
Pet *a_pet1 = new Dog(“Spike”);
a_pet1 -> Run();
static_cast<Cat *>(a_pet2) -> MakeSound();
a_pet2 -> Run();
static_cast<Dog *>(a_pet1) -> MakeSound();
return 0;
};

6.2.7

Image 1:

This image shows one final example of type compatibility. The code has been written out below.

#include <iostream>
#include <string>
using namespace std;
class Pet {
protected:
string Name;
public:
Pet(string n) {Name = n; }
void Run(void) {cout<<Name<<”: i’m running”<<endl; }
};
class Cat : public Pet {
public:
Cat(string n) : Pet(n) {};
void MakeSound(void) {cout<<Name<<”: Meow! Meow!”<<endl; }
};
class Persian : public Cat {
public:
Persian(string n) : Cat(n) {};
};
int main(void) {
Pet *a_pet1;
Persian *a_persian;
a_pet = a_persian = new Persian(“Mr. Bigglesworth”);
a_persian -> Makesound();
static_cast<Persian *>(a_pet) -> MakeSound();
return 0;
};

6.3.1

Image 1:

This image shows an example of overriding a method in a subclass in C++. The example code is written out below.

#include <iostream>
#include <string>
using namespace std;
class Pet {
protected:
string Name;
public:
Pet(string n) {Name = n; }
void MakeSound(void) {cout<<Name<<”the pet says: Shh! Shh!”<<endl; }
};
class Cat : public Pet {
public:
Cat(string n) : Pet(n) {}
void MakeSound(void) {cout<<Name<<”the cay says: Meow! Meow!”<<endl; }
};
class Dog : public Pet {
public:
Dog(string n) : Pet(n) {}
void MakeSound(void) {cout<<Name<<”the dog says: Woof! Woof!”<<endl; }
};
int main(void) {
Cat *a_cat;
Dog *a_dog;
Pet *a_pet1 = new Cat(“Kitty”);
Pet *a_pet1 = new Dog(“Doggie”);
a_cat -> MakeSound();
static_cast<Pet *>(a_Cat) -> MakeSound();
a_dog -> MakeSound();
static_cast<Pet *>(a_dog) -> MakeSound();
return 0;
}

6.3.2

Image 1:

This image shows another example of overriding a method in a subclass. The code is written out below.

#include <iostream>
using namespace std;
class Pet {
protected:
string Name;
public:
Pet(string n) {Name = n; }
void MakeSound(void) {cout<<Name<<”the pet says: Shh! Shh!”<<endl; }
};
class Cat : public Pet {
public:
Cat(string n) : Pet(n) {}
void MakeSound(void) {cout<<Name<<”the cay says: Meow! Meow!”<<endl; }
};
class Dog : public Pet {
public:
Dog(string n) : Pet(n) {}
void MakeSound(void) {cout<<Name<<”the dog says: Woof! Woof!”<<endl; }
};
int main(void) {
	Pet *a_pet1, *a_pet2;
	Cat *a_cat;
	Dog *a_dog;

Pet *a_pet1 = new Cat(“Kitty”);
Pet *a_pet2 = new Dog(“Doggie”);
	a_pet1 -> Makesound();
	a_cat -> Makesound();
	a_pet2 -> Makesound();
	a_dog -> Makesound();
	return 0;
}

6.3.3

Image 1:

This image shows another example of overriding a method in a subclass, this time with polymorphism included. The code is written out below.

#include <iostream>
using namespace std;
class Pet {
protected:
string Name;
public:
Pet(string n) {Name = n; }
virtual void MakeSound(void) {cout<<Name<<”the pet says: Shh! Shh!”<<endl; }
};
class Cat : public Pet {
public:
Cat(string n) : Pet(n) {}
void MakeSound(void) {cout<<Name<<”the cay says: Meow! Meow!”<<endl; }
};
class Dog : public Pet {
public:
Dog(string n) : Pet(n) {}
void MakeSound(void) {cout<<Name<<”the dog says: Woof! Woof!”<<endl; }
};
int main(void) {
	Pet *a_pet1, *a_pet2;
	Cat *a_cat;
	Dog *a_dog;

Pet *a_pet1 = new Cat(“Kitty”);
Pet *a_pet2 = new Dog(“Doggie”);
	a_pet1 -> Makesound();
	a_cat -> Makesound();
	static_cast<pet *>(a_cat) -> Makesound();
	a_pet2 -> Makesound();
	a_dog -> Makesound();
	static_cast<pet *>(a_dog) -> Makesound();
	return 0;
}

6.3.4

Image 1:

This image shows another example of overriding a method in a subclass with polymorphism included. The code is written out below.

#include <iostream>
using namespace std;
class Pet {
protected:
string Name;
public:
Pet(string n) {Name = n; MakeSound();}
virtual void MakeSound(void) {cout<<Name<<”the pet says: Shh! Shh!”<<endl; }
};
class Cat : public Pet {
public:
Cat(string n) : Pet(n) {}
void MakeSound(void) {cout<<Name<<”the cay says: Meow! Meow!”<<endl; }
};
class Dog : public Pet {
public:
Dog(string n) : Pet(n) {}
void MakeSound(void) {cout<<Name<<”the dog says: Woof! Woof!”<<endl; }
};
int main(void) {
Cat *a_cat;
	Dog *a_dog;

	a_cat = new Cat(“Kitty”);
	a_dog = new Dog(“Doggie”);
	return 0;
}

6.3.5

Image 1:

This image shows another example of overriding a method in a subclass with polymorphism included. The code is written out below.

#include <iostream>
using namespace std;
class Pet {
protected:
string Name;
public:
Pet(string n) {Name = n;}
virtual void MakeSound(void) {cout<<Name<<”the pet says: Shh! Shh!”<<endl; }
void WakeUp(void) {MakeSound(); }
};
class Cat : public Pet {
public:
Cat(string n) : Pet(n) {}
void MakeSound(void) {cout<<Name<<”the cay says: Meow! Meow!”<<endl; }
};
class Dog : public Pet {
public:
Dog(string n) : Pet(n) {}
void MakeSound(void) {cout<<Name<<”the dog says: Woof! Woof!”<<endl; }
};
int main(void) {
Cat *a_cat;
	Dog *a_dog;

	a_cat = new Cat(“Kitty”);
	a_cat -> WakeUP();
	a_dog = new Dog(“Doggie”);
	a_dog -> WakeUP();
	return 0;
}

6.4.1

Image 1:

This image shows an example of passing an object as a function parameter in C++. The example code has been written out below.

#include <iostream>
#include <string>
using namespace std;
class Pet {
protected:
string Name;
public:
	void NameMe(string name) {this -> name = name; }
	void MakeSound(void) {cout<<name<<” says: no comments”<<endl; }
};
void PlayWithPetByPointer(string name, Pet *pet) {
	pet -> NameMe(name);
	pet -> MakeSound();
}
void PlayWithPetByReference(string name, Pet &pet) {
	pet.NameMe(name);
	pet.Makesound();
}
int main(void) {
	Pet *P1 = new Pet;
	Pet p2;
	PlayWithPetByPointer(“anonymous”, p1);
	PlayWithPetByReference(“no_name”, p2);
	PlayWithPetByPointer(“no_name”, &p2);
	PlayWithPetByReference(“anonymous”, *p1);
	return 0;

}

6.4.2

Image 1:

This image shows an example of passing an object by a value in C++. The code is written out below.

#include <iostream>
#include <string>
using namespace std;
class Pet {
protected:
string Name;
public:
	void NameMe(string name) {this -> name = name; }
	void MakeSound(void) {cout<<name<<” says: no comments”<<endl; }
};
void NamePetByValue(string name, Pet pet) {
	pet.NameMe(name);
}
void NamePetByPointer(string name, Pet *pet) {
	pet -> NameMe(name);
}
void NamePetByRefrence(string name, Pet &pet) {
	pet.NameMe(name);
}
int main(void) {
	Pet pet;
	Pet.NameMe(“no_Name”);
	NamePetByValue(“Alpha”, pet);
	Pet.MakeSound();
	NamePetByPointer(“Beta”, &pet);
	Pet.MakeSound();
	NamePetByRefrence(“Gamma”, Pet);
	Pet.MakeSound();
	return 0;
}

6.4.3

Image 1:

This image shows an example of passing an object of a subclass by reference in C++. The code is written out below.

#include <iostream>
#include <string>
using namespace std;
class Pet {
protected: string Name;
public: Pet(string name) {this -> name = name; }
	void MakeSound(void) {cout<<name<<” is silent :(“<<endl; }
};
class Dog : public Pet {
public: Dog(string name) : Pet(name) {}
void MakeSound(void) {cout<<Name<<”says: Woof!”<<endl; }
};
class GermanSheperd : public Dog {
public: GermanSheperd(string name) : Dog(name) {}
void MakeSound(void) {cout<<Name<<”says: Wuff!”<<endl; }
};
class MastinEspanol : public Dog {
public: MastinEspanol(string name) : Dog(name) {}
void MakeSound(void) {cout<<Name<<”says: Guau!”<<endl; }
};
void PlayWithPet(Pet &pet) {
	pet.MakeSound();
}
int main(void) {
	Pet pet(“creature”);
	Dog dog(“Dog”);
	GermanSheperd gs(“Hound”);
	MastinEspanol mes(“Perro”);
	PlayWithPet(pet);
	PlayWithPet(dog);
 	PlayWithPet(gs);
	PlayWithPet(mes);
	return 0;
}

6.4.4

Image 1:

This image shows another example of passing an object of a subclass by pointer in C++. The code is written out below.

#include <iostream>
#include <string>
using namespace std;
class Pet {
protected: string Name;
public: Pet(string name) {this -> name = name; }
	void MakeSound(void) {cout<<name<<” is silent :(“<<endl; }
};
class Dog : public Pet {
public: Dog(string name) : Pet(name) {}
void MakeSound(void) {cout<<Name<<”says: Woof!”<<endl; }
};
class GermanSheperd : public Dog {
public: GermanSheperd(string name) : Dog(name) {}
void MakeSound(void) {cout<<Name<<”says: Wuff!”<<endl; }
};
class MastinEspanol : public Dog {
public: MastinEspanol(string name) : Dog(name) {}
void MakeSound(void) {cout<<Name<<”says: Guau!”<<endl; }
};
void PlayWithPet(Pet &pet) {
	pet.MakeSound();
}
int main(void) {
	Pet  *pet = new Pet(“creature”);
	Dog  *dog = new Dog(“Dog”);
	GermanSheperd *gs = new GermanShepherd(“Hund”);
	MastinEspanol *mes = new MastinEspanol(“Perro”);
	PlayWithPet(pet);
	PlayWithPet(dog);
 	PlayWithPet(gs);
	PlayWithPet(mes);
	return 0;
}

6.4.5

Image 1:

This image shows an example of the dynamic_cast operator applied to a pointer in C++. The code is written out below.

#include <iostream>
#include <string>
using namespace std;
class Pet {
protected: string Name;
public: Pet(string name) : name = (name) {}
	void MakeSound(void) {cout<<name<<” is silent :(“<<endl; }
};
class Dog : public Pet {
public: Dog(string name) : Pet(name) {}
void MakeSound(void) {cout<<Name<<”says: Woof!”<<endl; }
};
class GermanSheperd : public Dog {
public: GermanSheperd(string name) : Dog(name) {}
void MakeSound(void) {cout<<Name<<”says: Wuff!”<<endl; }
void Laufen(void) {cout<<name<<”runs (gs)!”<<endl; }
};
class MastinEspanol : public Dog {
public: MastinEspanol(string name) : Dog(name) {}
void MakeSound(void) {cout<<Name<<”says: Guau!”<<endl; }
void Ejecutar(void) {cout<<name<<” runs (mes)!”<<endl; }
};
void playWithPet(Pet *pet) {
	GermanSheperd *gs;
	MastinEspanol *mes;
	pet -> MakeSound();
	if(gs = dynamic_cast<GermanSheperd *>(pet))
		gs -> Laufen();
	if(mes = dynamic_cast<MastinEspanol *>(pet))
		mes -> Ejecutar();
}
int main(void) {
	Pet *pet = new Pet(“creature”);
	Dog *dog = new Dog(“Dog”) 
	GermanShepherd *gs = new GermanShepherd(“Hund”);
	MastinEspanol *mes = new MastinEspanol(“Perro”);
	PlayWithPet(pet);
	PlayWithPet(dog);
 	PlayWithPet(gs);
	PlayWithPet(mes);
	return 0;
}

6.4.6

Image 1:

This image shows another example of the dynamic cast operator that has been applied to a reference. The code is written out below.

#include <iostream>
#include <string>
using namespace std;
class Pet {
protected: string Name;
public: Pet(string name) : name = (name) {}
	void MakeSound(void) {cout<<name<<” is silent :(“<<endl; }
};
class Dog : public Pet {
public: Dog(string name) : Pet(name) {}
void MakeSound(void) {cout<<Name<<”says: Woof!”<<endl; }
};
class GermanSheperd : public Dog {
public: GermanSheperd(string name) : Dog(name) {}
void MakeSound(void) {cout<<Name<<”says: Wuff!”<<endl; }
void Laufen(void) {cout<<name<<”runs (gs)!”<<endl; }
};
class MastinEspanol : public Dog {
public: MastinEspanol(string name) : Dog(name) {}
void MakeSound(void) {cout<<Name<<”says: Guau!”<<endl; }
void Ejecutar(void) {cout<<name<<” runs (mes)!”<<endl; }
};
void playWithPet(Pet &pet) {
	pet.MakeSound();
	dynamic_cast<GermanShepherd &>(pet).Laufen();
	dynamic_cast<MastinEspanol &>(pet).Ejecutar();
}
int main(void) {
	Pet pet(“creature”);
	Dog dog(“Dog”);
	GermanShepherd gs(“Hund”); 
	MastinEspanol mes(“Perro”);						
	PlayWithPet(pet);
	PlayWithPet(dog);
 	PlayWithPet(gs);
	PlayWithPet(mes);
	return 0;
}

6.4.7

Image 1:

This image shows another example of the dynamic cast operator applied to a reference. The code is written out below.

#include <iostream>
#include <string>
using namespace std;
class Pet {
protected: string Name;
public: Pet(string name) : name = (name) {}
	void MakeSound(void) {cout<<name<<” is silent :(“<<endl; }
};
class Dog : public Pet {
public: Dog(string name) : Pet(name) {}
void MakeSound(void) {cout<<Name<<”says: Woof!”<<endl; }
};
class GermanSheperd : public Dog {
public: GermanSheperd(string name) : Dog(name) {}
void MakeSound(void) {cout<<Name<<”says: Wuff!”<<endl; }
void Laufen(void) {cout<<name<<”runs (gs)!”<<endl; }
};
class MastinEspanol : public Dog {
public: MastinEspanol(string name) : Dog(name) {}
void MakeSound(void) {cout<<Name<<”says: Guau!”<<endl; }
void Ejecutar(void) {cout<<name<<” runs (mes)!”<<endl; }
};
void playWithPet(Pet &pet) {
	pet.MakeSound();
	try {
		dynamic_cast<GermanShepherd &>(pet).Laufen();
	}catch(...) {}
	try {
		dynamic_cast<MastinEspanol &>(pet).Ejecutar();
	}catch(...) {}

}
int main(void) {
	Pet pet(“creature”);
	Dog dog(“Dog”);
	GermanShepherd gs(“Hund”); 
	MastinEspanol mes(“Perro”);						
	PlayWithPet(pet);
	PlayWithPet(dog);
 	PlayWithPet(gs);
	PlayWithPet(mes);
	return 0;
}

6.5.1

Image 1:

This image shows an example of a copying constructor in C++. The example code has been written out below.

#include <iostream>
using namespace std;
class Class {
	int data;
public:
	Class(int value) :data(value) {}
	void increment(void) { data++; }
	int value(void) {return data;}
};
int main(void) {
	Class o1(123);
	Class o2 = o1;
	Class o3(o2);

	o1.increment();
	cout<<01.value()<<endl;
	cout<<02.value()<<endl;
	cout<<03.value()<<endl;

	return 0;
}

6.5.2

Image 1:

This image shows another example of copying constructors. The code is written out below.

#include <iostream>
using namespace std;
class Class {
	int *data;
public:
	Class(int value) {
		data = new unit;
		*data = value;
	}
	void increment(void) {(*data)++;}
	int value(void) {return *data; }
};
int main(void) {
	Class o1(123);
	Class o2 = o1;
	Class o3(o2);
	o1.increment();
	cout<<01.value()<<endl;
	cout<<02.value()<<endl;
	cout<<03.value()<<endl;
	return 0;
}

6.5.3

Image 1:

This image shows another example of a copying constructor. The code has been written out below.

#include <iostream>
using namespace std;
class Class {
	int *data;
public:
	Class(int value) {
		data = new int;
		*data = value;
	}
	void increment(void) {(*data)++;}
	int value(void) {return *data; }
};
int main(void) {
	Class o1(123);
	Class o2(o1.value());
	Class o3(o2.value());
	o1.increment();
	cout<<01.value()<<endl;
	cout<<02.value()<<endl;
	cout<<03.value()<<endl;
	return 0;
}

6.5.4

Image 1:

This image shows another example of a copying constructor. The code has been written out below.

1. include <iostream>

using namespace std; class Class {

	int *data;

public:

	Class(int value) {
		data = new int;
		*data = value;
	}
	Class(Class &Source) {
		Data = new int;
		*data = source.value();
	}
	void increment(void) { (*data)++;}
	int value(void) {return *data; }

}; int main(void) {

	Class o1(123);
	Class o2 = o1;
	Class o3(o2);
	o1.increment();
	cout<<01.value()<<endl;
	cout<<02.value()<<endl;
	cout<<03.value()<<endl;
	return 0;

}

6.5.5

Image 1:

This image shows another example of a copying constructor. The code has been written out below.

#include <iostream>
using namespace std;
class Dummy {
public:
	Dummy(int value) {}
	Dummy(Dummy &source) {
		cout<<”Hi from the copy constructor!”<<endl;
	}
};
void DoSomething(Dummy ob) {
	cout<<”i’m here!”<<endl;
}
int main(void) {
	Dummy o1(123);
	DoSomething(o1);
	return 0;
}

6.5.6

Image 1:

This image shows another example of a copy constructor. The code is written out below.

#include <iostream>
using namespace std;
class Dummy {
private:
	Dummy(Dummy &source) {}
Public:
	Dummy(int value) {}
};
void DoSomething(Dummy ob) {
	cout<<”i’m here!”<<endl;
}
int main(void) {
	 Dummy o1(123);
	Dummy o2 = o1;
	 DoSomething(o1);
	 return 0;
}

6.5.7

Image 1:

This image shows an example of a default constructor in C++. The code has been written out below.

#include <iostream>
using namespace std;
class NoConstructorAtAll {
public:
	int i;
	float f;
	void Display(void) {cout<<”i=”<<i<<”,f=”<<f<<endl; }
};
int main(void) {
	NoConstructorsAtAll o1;
	NoConstructorsAtAll *o2;
	o2 = new NoConstructorsAtAll;
	o1.Display();
	o2 -> Display();
	return 0;
}

6.5.8

Image 1:

This image shows another example of a default constructor. The code is written out below.

#include <iostream>
using namespace std;
class WithConstructor {
public:
	int i;
	float f;
	WithConstructor(int a, float b) : i(a), f(b) {}
	void display(void) {cout<<”i=”<<i<<”,f=”<<f<<endl; }
};
int main(void) {
	WithConstructor o1;
	WithConstructor o2;
	o2 = new WithConstructor;
	o1.Display();
	02 -> Display();
	return 0;
};

6.5.9

Image 1:

This image shows another example of a default constructor. The code has been written out below.

#include <iostream>
using namespace std;
class WithConstructor {
public:
	int i;
	float f;
	WithConstructor(int a = 0, float b = 0) : i(a), f(b) {}
	void display(void) {cout<<”i=”<<i<<”,f=”<<f<<endl; }
};
int main(void) {
	WithConstructor o1;
	WithConstructor *o2;
	o2 = new WithConstructor;
	o1.Display();
	02 -> Display();
	return 0;
};

6.5.10

Image 1:

This image shows an example of compositions vs constructors in C++. The code is written out below.

#include <iostream>
using namespace std;
class A {
public:
	void Do(void) {cout<<”A is doing something”<<endl; }
};
Class B {
Public:
	void Do(void) {cout<<”B is doing something”<<endl; }
};
Class Compo {
public:
	A f1;
	B f2;
};
int main(void) {
	Compo co;
	co.f1.Do();
	co.f2.Do();
	return 0;
}

6.5.11

Image 1:

This image shows another example of compositions vs constructors. The code is written out below.

#include <iostream>
using namespace std;
class A {
public:
	A(A &src) {cout<<”copying A...”<<endl; }
	A(void) { }
	void Do(void) {cout<<”A is doing something”<<endl; }
};
Class B {
Public:
	B(B &src) {cout<<”copying B...”<<endl; }
	B(void) { }
	void Do(void) {cout<<”B is doing something”<<endl; }
};
Class Compo {
public:
	Compo(void) { };
	A f1;
	B f2;
};
int main(void) {
	Compo co1;
	Compo co2 = co1;
	co.f1.Do();
	co.f2.Do();
	return 0;
}

6.5.12

Image 1:

This image shows another example of compositions vs constructors. The code is written out below.

#include <iostream>
using namespace std;
class A {
public:
	A(A &src) {cout<<”copying A...”<<endl; }
	A(void) { }
	void Do(void) {cout<<”A is doing something”<<endl; }
};
Class B {
Public:
	B(B &src) {cout<<”copying B...”<<endl; }
	B(void) { }
	void Do(void) {cout<<”B is doing something”<<endl; }
};
Class Compo {
public:
	Compo(Compo &src) {cout<<”Copying Compo...”<<endl; }
	Compo(void) { };
	A f1;
	B f2;
};
int main(void) {
	Compo co1;
	Compo co2 = co1;
	co.f1.Do();
	co.f2.Do();
	return 0;
}

6.6.1

Image 1:

This image shows the C++ constant operator , otherwise known as const. This has been written out below.

CONST

6.6.2

Image 1:

This image shows an example of constant variables and their declarations in C++. The code is written out below.

const int size1 = 100;
int const size2 = 100;

6.6.3

Image 1:

This image shows an example of constant aggregates and their declarations. The code is written out below.

cons tint points[5] = {1,2,4,8,16};
const struct {int key; } data = {10};

6.6.4

Image 1:

This image shows an example of constant pointers and their declarations. The code is written out below.

int arr[5] = {1, 2, 4, 8, 16};
int * const iptr = arr + 2;
char * const cptr = “Why?”;

6.6.5

Image 1:

This image shows an example of pointers to constants, and their declarations. The code is written out below.

int arr[5] = {1, 2, 4, 8, 16};
cons int *iptr = arr + 2;
const char *cptr = “Why?”;

6.6.6

Image 1:

This image shows an example of constant pointers to constants, and their declarations. The code has been written out below.

int arr[5] = {1, 2, 4, 8, 16};
const int * const iptr = arr + 2;
const char * const cptr = “Why?”;

6.6.7

Image 1:

This image shows an example of constant function parameters which have been passed by value. The example code is written out below.

int fun(const int n) {
	return n * n;
}

6.6.8

Image 1:

This image shows an example of constant function parameters which have been passed by reference. The code has been written out below.

int fun(const int &n) {
	return n++;
}

6.6.9

Image 1:

This image shows an example of constant function results, and their declarations. The code is written out below.

const char *fun(void) {
	return “Caution!”;
}

6.6.10

Image 1:

This image shows an example of constant class variables. The code is written out below.

class Class{
private:
	const int field;
public:
	Class(int n) : field(n) {};
	Class(Class &c) : field(0) {};
	Class(void) : field(1) {};
};

6.6.11

Image 1:

This image shows an example of constant objects in C++. The code is written out below.

class Class {
public:
	int field;
	Class(int n) : field(n) {};
	Class(Class &c) : field(0) {};
	Class(void) : field(1) {};
	void set(int n) {field = n;} 
	int get(void) {return field;}
};

6.6.12

Image 1:

This image shows an example of constant member functions in C++. The code is written out below.

class Class {
public:
	int field;
	Class(int n) : field(n) {};
	Class(Class &c) : field(0) {};
	Class(void) : field(1) {};
	void set(int n) {field = n;} 
	int get(void) const {return field;}
};

6.7.1

Image 1:

This image shows a kitten and a small dog sleeping next to each other, with the kitten looking at the camera lens. The image is titled: "Friend or Foe?".

6.7.2

Image 1:

This image shows an example of a friend class program written in C++. The code is written out below.

#include <iostream>
using namespace std;
class Class {
friend class Friend;
private:  
	int field;
	void print(void) {cout<<”it’s a secret, that field = “<<field<<endl; }
};
class Friend {
public:
	void Dolt(Class &c) {c.field = 100; c.print(); }
};
int main(void) {
	Class o;
	Friend f;

	f.Dolt(o);
	return 0;
}

6.7.3

Image 1:

This image shows an example of the updated friend class program. The code is written out below.

#include <iostream>
using namespace std;
class A {
friend class B;
friend class C;
private:  
	int field;
protected:
	void print(void) { cout<<”it’s a secret, that field = “<<field<<endl; }
};
class C {
public:
	void Dolt(A &a) {a.print(); }
};
Class B {
public:
	void Dolt(A &a, C &c) {a.field = 111; c.Dolt(a); }
};
int main(void) {
	A a; B b; C c;

	b.Dolt(a,c);
	return 0;
};

6.7.4

Image 1:

This image shows an example of a friend functions program. The code is written out below.

#include <iostream>
using namespace std;
class A;
class C {
public:
	void dec(A &a);
};
class A {
friend class B;
friend void C::dec(A&);
friend void Dolt(A&);
private:
	int field;
protected:
	void print(void) { cout<<”it’s a secret, that field = “<<field<<endl; }
};
void C::dec(A &a) {a.field--;}
class B {
public:
	void Dolt(A &a) {a.print(); }
};
Void Dolt(A &a) {
	a.field = 99;
}
int main(void) {
	A a, B b; C c;

	Dolt(a);
	b.Dolt(a);
	return 0;
}