typedef struct complex {
  double          r, i;
} Complex;

extern "C" Complex Add(Complex z, Complex w);
extern "C" Complex Sub(Complex z, Complex w);
extern "C" Complex Mul(Complex z, Complex w);
extern "C" Complex Div(Complex z, Complex w);
extern "C" Complex Adds(double a, Complex z);
extern "C" Complex Muls(double a, Complex z);
extern "C" Complex Divs(double a, Complex z);
extern "C" Complex Double2Complex(double re, double im);
extern "C" Complex Exp(Complex z);
extern "C" double  Cabs(Complex z, Complex w);
extern "C" void    PrintC(Complex z);

extern "C" void OpenWindow(int width, int height);
extern "C" void CloseWindow();
extern "C" void FlushWindow();
extern "C" void DrawLine(int y, int line[]);
extern "C" void DrawPoint(int x, int y, int color);
extern "C" void DrawCircle(int x, int y, int radius, int color);
extern "C" void WaitForButton(int *x, int *y, int *button);
extern "C" void DrawRectangle(int x, int y, int width, int height);
extern "C" void FillRectangle(int x, int y, int width, int height);
extern "C" void SetColor(int);
extern "C" void FillArc(int x, int y, int width, int height, int angle1, int angle2);