用C++绘制圆形

    # define PAI 3.1415926
    # define B 0.809
    # include "graphics.h"
    #include "math.h"
    int main()
    {
    int i,j,k,x0,y0,x,y,driver,mode;
    float a;
    driver=CGA;mode=CGAC0;
    initgraph(&driver,&mode,"");
    setcolor(3);
    setbkcolor(GREEN);
    x0=150;y0=100;
    circle(x0,y0,10);
    circle(x0,y0,20);
    circle(x0,y0,50);
    for(i=0;i<16;i++)
    {
        a=(2*PAI/16)*i;
        x=ceil(x0+48*cos(a));
        y=ceil(y0+48*sin(a)*B);
        setcolor(2); line(x0,y0,x,y);
    }
    setcolor(3);circle(x0,y0,60);
    /*