void Circle::print_char(int x1,int x2)

{

    int i;

    // 计算这一行的宽度，终端最多显示80列

    int n = max(x1, x2) + ;

    n = n >  ?  : n;

    for (i = ; i < n; i++)

    {

        if (i == x1 || i == x2)

            printf("*");

        else

             printf(" ");

    }

     printf("\n");

}

void Circle::Draw()

{

    int r=(int)semidiameter;

    int x1, x2, y;

   int d =  * r;

    int offset;

    for(y = ; y <= d; y++)

     {

         /*终端字符宽高比为2:1*/

        offset = (int)(0.5 + sqrt((double)(r*r - (y-r)*(y-r)))*2.0);

        x1 = d - offset;

        x2 = d + offset;

        print_char(x1, x2);

    }

}