Buch/pointer3.cpp at main · mgaeckler1964/Buch · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
/*
	pointer3.cpp: demonstration of abstract classes
*/

#include <iostream>

class Graphic
{
	public:
	virtual void show() const = 0;
	virtual ~Graphic()
	{
	}
};

class Punkt : public Graphic
{
	double x, y;

	public:
	Punkt( double x, double y ) : x(x), y(y)
	{
	}

	virtual void show() const
	{
		std::cout << "Punkt (" << x << ',' << y << ')' << std::endl;
	}
};

class Kreis : public Punkt
{
	double r;

	public:
	Kreis( double x, double y, double r ) : Punkt(x, y), r(r)
	{
	}

	virtual void show() const
	{
		Punkt::show();
		std::cout << "Radius " << r << std::endl;
	}
};

void showObject( const Graphic &obj )
{
	obj.show();
}

int main( void )
{
	Punkt	punkt( 2, 3 );
	Kreis	kreis( 5, 6, 1 );

	showObject( punkt );
	showObject( kreis );

	return 0;
}