hour07_3.cpp

《24学时精通c++》的随书源码的下半部分。欢迎下载学习。

 // Demonstrates declaration of a class and
 // definition of class methods,
 
 #include <iostream>      // for std::cout
 
 class Cat                   // begin declaration of the class
 {
 public:                     // begin public section
     int GetAge();           // accessor function
     void SetAge (int age);  // accessor function
     void Meow();            // general function
     int itsAge;             // member variable -- public now!
 };
 
 // GetAge, Public accessor function
 // returns value of itsAge member
 int Cat::GetAge()
 {
     return itsAge;
 }
 
 // definition of SetAge, public
 // accessor function
 // sets itsAge member
 void Cat::SetAge(int age)
 {
    // set member variable its age 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;
     Frisky.SetAge(5);
     Frisky.Meow();

     itsAge++;
   // The Line above will give a compiler error because there is no atomic variable itsAge.
   // Comment it out and recompile.

     Frisky.itsAge++;
   // The Line above should compile because now itsAge is public. Instead of seeing 5 printed
   // below, you should now see 6.

     std::cout << "Frisky is a cat who is " ;
     std::cout << Frisky.GetAge() << " years old.\n";
     Frisky.Meow();
     return 0;
 }