MandelbrotSet 分形艺术（C++实现）

转自 EasyX，不过我重构了代码。
运行结果：
源程序：
 1 // MandelbrotSet.cpp
 2 
 3 #include "graphics.h"
 4 #include <conio.h>
 5 
 6 struct Complex
 7 {
 8     double re;
 9     double im;
10 
11 public:
12     Complex operator * (const Complex &other) const
13     {
14         Complex c;
15         c.re = this->re * other.re - this->im * other.im;
16         c.im = this->im * other.re + this->re * other.im;
17         return c;
18     }
19 
20     Complex operator + (const Complex &other) const
21     {
22         Complex c;
23         c.re = this->re + other.re;
24         c.im = this->im + other.im;
25         return c;
26     }
27 };
28 
29 void main()
30 {
31     // 初始化绘图窗口
32     initgraph(640, 480);
33 
34     /////////////////////////////////////////////////
35     // 绘制 Mandelbrot Set (曼德布洛特集)
36     /////////////////////////////////////////////////
37     Complex z, c;
38     for(int x = 0; x < 640; x++)
39     {
40         c.re = -2.1 + (1.1 - -2.1) * (x / 640.0);
41         for(int y = 0; y < 480; y++)
42         {
43             c.im = -1.2 + (1.2 - -1.2) * (y / 480.0);
44             z.re = z.im = 0;
45             int k;
46             for(k = 0; k < 180; k++)
47             {
48                 if ( z.re * z.re + z.im * z.im > 4.0 )    break;
49                 z = z * z + c;
50             }
51             putpixel(x, y, (k >= 180) ? 0 : HSLtoRGB((float)((k << 5) % 360), 1.0, 0.5));
52         }
53     }
54 
55     // 按任意键退出
56     _getch();
57     closegraph();
58 }