box.h

一本语言类编程书籍

// Box.h - Definition of the Box class
#ifndef BOX_H
#define BOX_H

class Box {
  public:
    Box(double aLength = 1.0, double aWidth = 1.0, double aHeight = 1.0); 
                                               // Constructor

    double volume() const;                     // Calculate Box volume

    double getLength()  const; 
    double getWidth() const;
    double getHeight()  const;

    bool operator<(const Box& aBox) const;        // Compare Box < Box 
    bool operator<(const double aValue) const;    // Compare Box < double value
    Box operator+(const Box& aBox) const;         // Function to add two Box objects	

private:
    double length;
    double width;
    double height;
};

// Function comparing Box object < Box object
inline bool Box::operator<(const Box& aBox) const {
  return volume() < aBox.volume();
}

// Function comparing Box object < double value
inline bool Box::operator<(const double aValue) const {
  return volume() < aValue;
}

// Function comparing double value < Box object
inline bool operator<(const double aValue, const Box& aBox) {
  return aValue < aBox.volume();
}

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

#endif