The Anatomy of a COM Server(Chapter 2 of COM and .NET Interoperability) part1

  1 // Interfaces.cpp : Defines the entry point for the console application.
  2 
  3 #include "stdafx.h"
  4 #include <iostream.h>
  5 #include "windows.h"
  6 
  7 // The interface.
  8 interface ICar
  9 {
 10     virtual void SpeedUp(long delta) = 0;        
 11     virtual void CurrentSpeed(long *currSp) = 0;
 12 };
 13 
 14 // The basic Car.
 15 class Car : public ICar
 16 {
 17 private:
 18     long m_currSpeed;
 19 public:
 20     Car() { m_currSpeed = 0; }    
 21     virtual ~Car(){}
 22 
 23     // ICar implementation. 
 24     void SpeedUp(long delta)
 25     {
 26         cout << "I am a basic car" << endl;
 27         m_currSpeed += delta;    
 28     }         
 29     void CurrentSpeed(long *currSp)
 30     {
 31         *currSp = m_currSpeed;    
 32     }         
 33 };
 34 
 35 // The wicked cool car.
 36 class HotRod: public ICar
 37 {
 38 private:
 39     long m_currSpeed;
 40 public:
 41     HotRod() { m_currSpeed = 0; }    
 42     virtual ~HotRod(){}
 43     // ICar implementation (massive turbo booster!). 
 44     void SpeedUp(long delta)
 45     {
 46         cout << "I am a hot rod!" << endl;
 47         m_currSpeed += (delta * 20);    
 48     }         
 49     void CurrentSpeed(long *currSp)
 50     {
 51         *currSp = m_currSpeed;    
 52     }         
 53 };
 54 
 55 // Not a Car.
 56 class CellPhone
 57 {};
 58 
 59 // Prototypes.
 60 void RevEngine(ICar* pCar);
 61 
 62 // Take the cars out for a test drive.
 63 int main(int argc, char* argv[])
 64 {
 65     // An array of ICar interfaces. 
 66     ICar* theCars[2];
 67     theCars[0] = new Car();
 68     theCars[1] = new HotRod(); 
 69 
 70     // Speed up each car 5 times. 
 71     for (int j = 0; j < 5; j++)
 72     {
 73         for(int i = 0; i < 2; i++)
 74         {
 75             theCars[i]->SpeedUp(10);
 76             long currSp =  0;
 77             theCars[i]->CurrentSpeed(&currSp);
 78             cout << "  ->Speed: " << currSp << endl;
 79         }
 80     }
 81 
 82     // Clean up memory.
 83     delete[] *theCars;
 84 
 85     // Uncomment to generate error.
 86     /*
 87     ICar car;
 88     car.CurrentSpeed(10);
 89     */
 90 
 91     // Better!
 92     ICar* pAnotherCar = new Car();
 93     ICar* pAnotherHotRod = new HotRod();
 94 
 95     // Rev the car.
 96     RevEngine(pAnotherCar);
 97     RevEngine(pAnotherHotRod);
 98     delete pAnotherCar;
 99     delete pAnotherHotRod;
100 
101     // Uncomment for error.
102     // CellPhone cp;
103     // RevEngine(cp);
104     return 0;
105 }
106 
107 void RevEngine(ICar* pCar)
108 {
109     cout << "Reving a car..." << endl;
110     long currSp = 0;
111 
112     for(int i = 0; i < 5; i++)
113     {
114         pCar->SpeedUp(10);
115         pCar->CurrentSpeed(&currSp);
116         cout << "Speed: " << currSp << endl;
117     }
118     for(i = 5; i > 0; i--)
119     {
120         pCar->SpeedUp(-10);
121         pCar->CurrentSpeed(&currSp);
122         cout << "Speed: " << currSp << endl;
123     }
124 }