list0604.cpp

来自「teach yourself C++ in 21 days 第五版」· C++ 代码 · 共 68 行

// 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;
}