C++经典算法题-用rectangle画方形

#include "graphics.h"
    main()
    {
        int x0,y0,y1,x1,driver,mode,i;
        driver=VGA;mode=VGAHI;
        initgraph(&driver,&mode,"");
        setbkcolor(YELLOW);
        x0=263;y0=263;y1=275;x1=275;
        for(i=0;i<=18;i++)
        {
            setcolor(1);
            rectangle(x0,y0,x1,y1);
            x0=x0-5;
            y0=y0-5;
            x1=x1+5;
            y1=y1+5;
        }
        settextstyle(DEFAULT_FONT,HORIZ_DIR,2);
        outtextxy(150,40,"How beautiful it is!");
        line(130,60,480,60);
        setcolor(2);
        circle(269,269,137);
    }