circles.cpp

C++&datastructure书籍源码,以前外教提供现在与大家共享

#include "canvas.h"

// show simple Canvas functions, change style and color of drawing

void circles(Canvas& c, const Point& p, double size)
// post: series of circles drawn on c, centered at p
//       initial size = size (decreased by 20% for each one
{
    color spectrum[] = {CanvasColor::RED,    CanvasColor::ORANGE, CanvasColor::YELLOW, 
                        CanvasColor::GREEN,  CanvasColor::BLUE,   CanvasColor::INDIGO,
                        CanvasColor::VIOLET};
    int k;
    for(k=0; k < 7; k++)
    {   c.SetColor(spectrum[k]);
        c.DrawCircle(p,size);
        size *= 0.80;
    }
}

int main()
{
    const int WIDTH = 250, HEIGHT = 150;
    Canvas c(WIDTH, HEIGHT, 20,20);
    circles(c, Point(WIDTH/4, HEIGHT/2),   WIDTH/4);
    c.SetFrame();
    circles(c, Point(3*WIDTH/4, HEIGHT/2), WIDTH/4);
    c.runUntilEscape();
    return 0;
}