C#中算术运算导致溢出

Question

private void pictureBox1_Paint(object sender, PaintEventArgs e)
        {
            // 获取用户输入的圆形中心点坐标，半径，等分长度
            double rx = Convert.ToDouble(textBox1.Text);
            double ry = Convert.ToDouble(textBox2.Text);
            double r = Convert.ToDouble(textBox3.Text);
            double d = Convert.ToDouble(textBox4.Text);

            // 创建绘图对象
            Graphics g = e.Graphics;
            g.Clear(Color.White);

            // 获取坐标轴原点的坐标
            double originX = this.ClientSize.Width / 2;
            double originY = this.ClientSize.Height / 2;

            // 绘制坐标轴

            Pen axisPen = new Pen(Color.Black, 2);
            g.DrawLine(axisPen, (float)originX, 0, (float)originX, this.ClientSize.Height);
            g.DrawLine(axisPen, 0, (float)originY, this.ClientSize.Width, (float)originY);

            // 计算圆形的点坐标
            double angle = Math.PI * 2 * d / r; // 每个角度的大小
            PointF[] pointF = new PointF[(int)(r / d)]; // 点数组

            for (int i = 0; i < r / d; i++)
            {
                double x = r * Math.Cos(angle * i) + rx + originX; // 计算x坐标
                double y = r * Math.Sin(angle * i) + rx + originY; // 计算y坐标
                pointF[i] = new PointF((float)x, (float)y); // 将坐标保存到数组中
            }
            // 绘制圆形
            Pen Pen = new Pen(Color.Red, 2);
            g.DrawPolygon(Pen, pointF);

            //保存数据到text文本文件中
            using (StreamWriter writer = new StreamWriter("coordinates.txt"))
            {
                for (int i = 0; i < r / d; i++)
                {
                    writer.WriteLine($"({r * Math.Cos(angle * i) + rx}, {r * Math.Sin(angle * i) + rx}，{0})");
                }

            }
        }

各位牛人帮忙看一下为什么这句 PointF[] pointF = new PointF[(int)(r / d)]; // 点数组，会显示算术运算导致溢出？该怎么改正较好？我是初学者，求各位牛人指点

Answer 1

检查 d 是不是变成 0 了