C#递归算法之分而治之策略

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace DrawRuler
{
 public partial class Form1 : Form
 {
 public Form1()
 {
 InitializeComponent();
 }

 private void Form1_Load(object sender, EventArgs e)
 {
 }

 void drawRuler(float startPos, float endPos, int h)
 {
 float baseHeight =4;
 if (h > 0)
 {
 float midPos = (startPos + endPos) / 2;
 float height = h * baseHeight;
 drawMark(midPos, height);
 drawRuler(startPos, midPos, h - 1);
 drawRuler(midPos, endPos, h - 1);
 }
 }

 void drawMark(float pos, float height)
 {
 using (Graphics g = this.CreateGraphics())
 {
 float xOffset = 100 + pos;
 float yOffset = 100-height;
 SolidBrush brusuh = new SolidBrush(Color.Black);
 Pen p = new Pen(brusuh, 1);
 g.DrawLine(p, xOffset, yOffset, xOffset, 100);
 }
 }
 private void Form1_Paint(object sender, PaintEventArgs e)
 {
 #region 首先画一条直线
 using (Graphics g = e.Graphics)
 {
 float xOffset = 100;
 float yOffset = 100;
 int len = 300;
 SolidBrush brusuh = new SolidBrush(Color.Black);
 Pen p = new Pen(brusuh, 2);
 g.DrawLine(p, xOffset, yOffset, xOffset + len, yOffset);
 }
 #endregion

 drawRuler(0, 300, 3);
 }
 }
}