标题：课上练习代码——增加点击添加圆形处理的井字格

#include "graphics.h"

main()
{
    int driver=VGA,model=VGAHI;
    int i=0,j=0;
    int x,y;
    initgraph(&driver,&model,"");
    ege::initgraph(300,300);

    setbkcolor(BLACK);
    setcolor(WHITE);
    setfillstyle(SOLID_FILL,WHITE);
    for(j=0; j<3; j++)
    {

        for(i=0; i<3; i++)
        {
            if(j%2==0 && i%2==0)
            {
                bar(100*i,j*100,100*i+100,j*100+100);
            }
            if(j%2==1 && i%2==1)
            {
                bar(100*i,j*100,100*i+100,j*100+100);
            }

        }

    }

    for ( ; is_run(); delay_fps(120))
    {
        while (mousemsg())
        {
            mouse_msg m = getmouse();
            if (m.msg == mouse_msg_down)
            {
                x=m.x/100;
                y=m.y/100;
                setcolor(RED);
                setfillstyle(SOLID_FILL,RED);
                sector(x*100+100/2,y*100+100/2,0,360,50,50);
            }
        }
    }

}