prog1.cpp

C++语言程序设计题典

#include <iostream.h>
class Point        //抽象类
{
protected:
	int x,y;
public:
	Point(int i=0,int j=0) { x=i;y=j; }
	virtual void set()=0;
	virtual void draw()=0;
};
class Line:public Point
{
protected:
	int x1,y1;
public:
	Line(int i=0,int j=0,int m=0,int n=0):Point(i,j)
	{
		x1=m;y1=n;
	}
	void set()
	{
		cout << "Line::set() called" << endl;
	};
	void draw()
	{
		cout << "Line::draw() called" << endl;
	}
};
class Ellipse:public Point
{
protected:
	int x2,y2;
public:
	Ellipse(int i=0,int j=0,int p=0,int q=0):Point(i,j)
	{
		x2=p;y2=q;
	}
	void set()
	{
		cout << "Ellipse::set() called" << endl;
	}
	void draw()
	{
		cout << "Ellipse::draw() called" << endl;
	}
};
void drawobj(Point *p)
{
	p->draw();
}
void setobj(Point *p)
{
	p->set();
}
void main()
{
	Line *lineobj=new Line;
	Ellipse *ellipseobj=new Ellipse;
	drawobj(lineobj);
	drawobj(ellipseobj);
	setobj(lineobj);
	setobj(ellipseobj);
}