ex8_07.cpp

Visual C++ 2005的源代码

// Ex8_07.cpp
// Using a class template
#include <iostream>
using std::cout;
using std::endl;

class CBox                             // Class definition at global scope
{
  public:
    // Constructor definition
    CBox(double lv = 1.0, double wv = 1.0, double hv = 1.0): m_Height(hv)
    {
      m_Length = lv > wv? lv: wv;      // Ensure that 
      m_Width = wv < lv? wv: lv;       // length >= width
    }

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

    // Operator function for 'greater than' which
    // compares volumes of CBox objects.
    int CBox::operator>(const CBox& aBox) const
    {
      return this->Volume() > aBox.Volume();
    }

    // Function to compare a CBox object with a constant
    int operator>(const double& value) const
    {
      return Volume() > value;
    }

    // Function to add two CBox objects
    CBox operator+(const CBox& aBox) const
    {
      // New object has larger length & width, and sum of heights
      return CBox(m_Length > aBox.m_Length? m_Length:aBox.m_Length,
                  m_Width > aBox.m_Width? m_Width:aBox.m_Width,
                  m_Height + aBox.m_Height);
    }

    // Function to show the dimensions of a box
    void ShowBox() const
    {
      cout << m_Length << " " 
           << m_Width  << " " 
           << m_Height << endl;
    }

  private:
    double m_Length;                   // Length of a box in inches
    double m_Width;                    // Width of a box in inches
    double m_Height;                   // Height of a box in inches
};
// CSamples class template definition 
template <class T> class CSamples 
{
  public:
    // Constructors
    CSamples(const T values[], int count);
    CSamples(const T& value);
    CSamples(){ m_Free = 0; }

    bool Add(const T& value);          // Insert a value
    T Max() const;                     // Calculate maximum

  private:
    T m_Values[100];                   // Array to store samples
    int m_Free;                        // Index of free location in m_Values
};

// Constructor template definition to accept an array of samples
template<class T> CSamples<T>::CSamples(const T values[], int count)
{
  m_Free = count < 100? count:100;     // Don't exceed the array
  for(int i = 0; i < m_Free; i++)
    m_Values[i] = values[i];           // Store count number of samples
}

// Constructor to accept a single sample
template<class T> CSamples<T>::CSamples(const T& value)
{
  m_Values[0] = value;                 // Store the sample
  m_Free = 1;                          // Next is free
}

// Function to add a sample
template<class T> bool CSamples<T>::Add(const T& value)
{
  bool OK = m_Free < 100;              // Indicates there is a free place
  if(OK)
    m_Values[m_Free++] = value;        // OK true, so store the value
  return OK;
}

// Function to obtain maximum sample
template<class T> T CSamples<T>::Max() const
{
  T theMax = m_Free ? m_Values[0] : 0; // Set first sample or 0 as maximum
  for(int i = 1; i < m_Free; i++)      // Check all the samples
    if(m_Values[i] > theMax)
      theMax = m_Values[i];            // Store any larger sample
  return theMax;
}

int main()
{
  CBox boxes[] = {                          // Create an array of boxes
                   CBox(8.0, 5.0, 2.0),     // Initialize the boxes...
                   CBox(5.0, 4.0, 6.0),
                   CBox(4.0, 3.0, 3.0)
                 };

  // Create the CSamples object to hold CBox objects
  CSamples<CBox> myBoxes(boxes, sizeof boxes / sizeof CBox);

  CBox maxBox = myBoxes.Max();              // Get the biggest box
  cout << endl                              // and output its volume
       << "The biggest box has a volume of "
       << maxBox.Volume()
       << endl;
  return 0;
}