hour22_2.cpp

《24学时精通c++》的随书源码的下半部分。欢迎下载学习。

 // Listing 22.1
 #include <iostream>

 class Condition
 {
 public:
     Condition() { }
     virtual ~Condition() {}
     virtual void Log() = 0;
 };

 class Normal : public Condition
 {
 public:
     Normal() { Log(); }
     virtual ~Normal() { std::cout << "Normal Destructor\n"; }
     virtual void Log()
         { std::cout << "Logging normal conditions...\n"; }
 };

 class Error : public Condition
 {
 public:
     Error() {Log();}
     virtual ~Error() { std::cout << "Error Destructor\n"; }
     virtual void Log() { std::cout << "Logging error!\n"; }
 };

 class Alarm : public Condition
 {
 public:
     Alarm ();
     virtual   ~Alarm() { std::cout << "Alarm Destructor\n"; }
     virtual void Warn() { std::cout << "Warning!\n"; }
     virtual void Log() { std::cout << "General Alarm log\n"; }
     virtual void Call() = 0;
 };

 Alarm::Alarm()
 {
     Log();
    Warn();
 }

 class FireAlarm : public Alarm
 {
 public:
     FireAlarm(){Log();};
     virtual ~FireAlarm() { std::cout << "FireAlarm Destructor\n"; }
     virtual void Call() { std::cout<< "Calling Fire Dept.!\n"; }
     virtual void Log() { std::cout << "Logging fire call.\n"; }
 };

 int main()
 {
     int input;
     int okay = 1;
     Condition * pCondition;
     while (okay)
     {
         std::cout << "(0)Quit (1)Normal (2)Fire: ";
         std::cin >> input;
         okay = input;
         switch (input)
         {
         case 0:
             break;
         case 1:
             pCondition = new Normal;
             delete pCondition;
             break;
         case 2:
             pCondition = new FireAlarm;
             delete pCondition;
             break;
         default:
             pCondition = new Error;
             delete pCondition;
             okay = 0;
             break;
         }
     }
     return 0;
 }