Mega Code Archive
Implementing pure virtual functions
<![CDATA[
#include <iostream>
class Shape
{
public:
Shape(){}
virtual ~Shape(){}
virtual long GetArea() = 0;
virtual long GetPerim()= 0;
virtual void Draw() = 0;
private:
};
void Shape::Draw()
{
std::cout << "Abstract drawing mechanism!\n";
}
class Circle : public Shape
{
public:
Circle(int radius):itsRadius(radius){}
~Circle(){}
long GetArea() { return 3 * itsRadius * itsRadius; }
long GetPerim() { return 9 * itsRadius; }
void Draw();
private:
int itsRadius;
int itsCircumference;
};
void Circle::Draw()
{
std::cout << "Circle drawing routine here!\n";
Shape::Draw();
}
class Rectangle : public Shape
{
public:
Rectangle(int len, int width):
itsLength(len), itsWidth(width){}
virtual ~Rectangle(){}
long GetArea() { return itsLength * itsWidth; }
long GetPerim() {return 2*itsLength + 2*itsWidth; }
virtual int GetLength() { return itsLength; }
virtual int GetWidth() { return itsWidth; }
void Draw();
private:
int itsWidth;
int itsLength;
};
void Rectangle::Draw()
{
for (int i = 0; i<itsLength; i++)
{
for (int j = 0; j<itsWidth; j++)
std::cout << "x ";
std::cout << "\n";
}
Shape::Draw();
}
class Square : public Rectangle
{
public:
Square(int len);
Square(int len, int width);
~Square(){}
long GetPerim() {return 4 * GetLength();}
};
Square::Square(int len):Rectangle(len,len)
{}
Square::Square(int len, int width):Rectangle(len,width){
if (GetLength() != GetWidth())
std::cout << "Error, not a square... a Rectangle??\n";
}
int main()
{
Shape * sp;
sp = new Circle(5);
sp->Draw();
sp = new Rectangle(4,6);
sp->Draw();
sp = new Square (5);
sp->Draw();
return 0;
}
Circle drawing routine here!
Abstract drawing mechanism!
x x x x x x
Abstract drawing mechanism!
x x x x x
Abstract drawing mechanism!
]]>