C++经典算法题-用line画直线

#include "graphics.h"
    main()
    {
        int driver,mode,i;
        float x0,y0,y1,x1;
        float j=12,k;
        driver=VGA;mode=VGAHI;
        initgraph(&driver,&mode,"");
        setbkcolor(GREEN);
        x0=263;y0=263;y1=275;x1=275;
        for(i=0;i<=18;i++)
        {
            setcolor(5);
            line(x0,y0,x0,y1);
            x0=x0-5;
            y0=y0-5;
            x1=x1+5;
            y1=y1+5;
            j=j+10;
        }
        x0=263;y1=275;y0=263;
        for(i=0;i<=20;i++)
        {
            setcolor(5);
            line(x0,y0,x0,y1);
            x0=x0+5;
            y0=y0+5;
            y1=y1-5;
        }
    }