ex8_11.cpp

Beginning Visual C++ 6源码。Wrox。

// EX8_11.CPP
// Using a static data member in a class
#include <iostream>
using namespace std;

class CBox                           // Class definition at global scope
{
   public:
      static int objectCount;             // Count of objects in existence

      // Constructor definition
      CBox(double lv, double bv = 1.0, double hv = 1.0): m_Length(lv),
                                                         m_Breadth(bv),
                                                         m_Height(hv)
      {
         cout << endl << "Constructor called.";
         objectCount++;
      }

      CBox()                              // Default constructor
      {
         cout << endl
              << "Default constructor called.";
         m_Length = m_Breadth = m_Height = 1.0;
         objectCount++;
      }

      // Function to calculate the volume of a box
      double Volume() const
      {
         return m_Length*m_Breadth*m_Height;
      }

   private:
      double m_Length;                    // Length of a box in inches
      double m_Breadth;                   // Breadth of a box in inches
      double m_Height;                    // Height of a box in inches

};

int CBox::objectCount = 0;                // Initialize static member of 
						         // class CBox

int main()
{
   CBox boxes[5];                         // Array of CBox objects declared
   CBox cigar(8.0, 5.0, 1.0);              // Declare cigar box

   cout << endl << endl
        << "Number of objects (through class) = "
        << CBox::objectCount;
   
   cout << endl
        << "Number of objects (through object) = "
        << boxes[2].objectCount;

   cout << endl;
   return 0;
}