C#简单计算器如何实现小数点运算~望各位大虾帮忙解答
各位大虾看看，我这么写根本就不跟我小数点的概念~~~~~~很是郁闷了，还有怎么能实现打印结果为 2+3=5！
现在输入2显示（2），+显示空白，3只显示（3），=只显示（5）；
想要输入2显示（2），接着输入+显示（2+），输入3显示（2+3），输入=显示（2+3=5）；


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

namespace calc
{
  public partial class Form1 : Form
  {
  int a = 0;
  int b = 0;
  double result = 0.0;
  char c;
  bool joiy = true;

  public Form1()
  {
  InitializeComponent();
  }

  private void textBox1_TextChanged(object sender, EventArgs e)
  {
  Console.WriteLine(a);
  }

  private void button16_Click(object sender, EventArgs e)
  {
  if (joiy == false)
  {
  b = (int)result;
  joiy = true;
  }
  else
  {
  if (b == 0)
  {
  b = a;
  }
  else 
  {
  b -= a;
  }
  }
  a = 0;
  this.textBox1.Text = "";
  c = '_';
  }

  private void button17_Click(object sender, EventArgs e)
  {
  if (joiy == false)
  {
  b = (int)result;
  joiy = true;
  }
  else 
  {
  if (b == 0)
  {
  b = a;
  }
  else
  {
  b += a;
  }
  }
  a = 0;
  this.textBox1.Text = "";
  c = '+';
  }

  private void button14_Click(object sender, EventArgs e)
  {
  if (joiy == false)
  {
  b = (int)result;
  joiy = true;
  }
  else
  {
  if (b == 0)
  {
  b = a;
  }
  else
  {
  b *= a;
  }
  }
  a = 0;
  this.textBox1.Text = "";
  c='*';
  }

  private void button15_Click(object sender, EventArgs e)
  {
  if (joiy == false)
  {
  b = (int)result;
  joiy = true;
  }
  else
  {
  if (b == 0)
  {
  b = a;
  }
  else
  {
  b /= a;
  }
  }
  a = 0;
  this.textBox1.Text = "";