cylindr2.cpp

经典的<<C how to program>一书第三版的例程。非常适合于C的初学者。

// Fig. 19.10: cylindr2.cpp
// Member and friend function definitions 
// for class Cylinder.
#include "cylindr2.h"

// Cylinder constructor calls Circle constructor
Cylinder::Cylinder( double h, double r, int x, int y )
   : Circle( r, x, y )   // call base-class constructor
{ setHeight( h ); }

// Set height of Cylinder
void Cylinder::setHeight( double h ) 
   { height = ( h >= 0 ? h : 0 ); }

// Get height of Cylinder
double Cylinder::getHeight() const { return height; }

// Calculate area of Cylinder (i.e., surface area)
double Cylinder::area() const
{
   return 2 * Circle::area() +
          2 * 3.14159 * radius * height;
}

// Calculate volume of Cylinder
double Cylinder::volume() const
   { return Circle::area() * height; }

// Output Cylinder dimensions
ostream &operator<<( ostream &output, const Cylinder &c )
{
   output << static_cast< Circle >( c )
          << "; Height = " << c.height;

   return output;   // enables cascaded calls
}



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