4elist0604.cpp

《21天学通C＋＋》附盘的原代码。书上的每个例子在这里都有相应的C语言程序。

// Demonstrates declaration of  constructors and
// destructor for the Cat class
// Programmer created default constructor

#include <iostream>		// for cout

class Cat                   // begin declaration of the class
{
public:						// begin public section
	Cat(int initialAge);	// constructor
	~Cat();					// destructor
	int GetAge();			// accessor function
	void SetAge(int age);	// accessor function
	void Meow();
private:					// begin private section
	int itsAge;				// member variable
};

// constructor of Cat,
Cat::Cat(int initialAge)
{
   itsAge = initialAge;
}

Cat::~Cat()                 // destructor, takes no action
{
}

// GetAge, Public accessor function
// returns value of itsAge member
int Cat::GetAge()
{
	return itsAge;
}

// Definition of SetAge, public
// accessor function

void Cat::SetAge(int age)
{
	// set member variable itsAge to
	// value passed in by parameter age
	itsAge = age;
}

// definition of Meow method
// returns: void
// parameters: None
// action: Prints "meow" to screen
void Cat::Meow()
{
	std::cout << "Meow.\n";
}

// create a cat, set its age, have it
// meow, tell us its age, then meow again.
int main()
{
	Cat Frisky(5);
	Frisky.Meow();
	std::cout << "Frisky is a cat who is " ;
	std::cout << Frisky.GetAge() << " years old.\n";
	Frisky.Meow();
	Frisky.SetAge(7);
	std::cout << "Now Frisky is " ;
	std::cout << Frisky.GetAge() << " years old.\n";
	return 0;
}