C#计算器编写代码

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 Calculator
{
 public partial class Form1 : Form
 {
  private List<double> value_list = new List<double>();//存用户输入的数字
  private List<int> operator_list = new List<int>();//存用户输入的运算符，定义+为0，-为1，×为2，÷为3
  //状态记录
  private bool add_flag = false;//+按下
  private bool minus_flag = false;//-按下
  private bool multi_flag = false;//×按下
  private bool div_flag = false;//÷按下
  private bool result_flag = false;//=按下
  private bool can_operate_flag = false;//按下=是否响应

  public Form1()
  {
   InitializeComponent();
  }

  //数字键按下，含0与.，类似000001223这类情况这里允许，因为C#可以讲000001223自己转化为1223
  private void num_down(string num)
  {
   if (add_flag || minus_flag || multi_flag || div_flag || result_flag)
   {
    if (result_flag)//按下等号，刚刚算完一个运算的状态
    {
     label1.Text = "";
    }
    textBox1.Clear();//如果用户刚刚输入完一个运算符
    add_flag = false;
    minus_flag = false;
    multi_flag = false;
    div_flag = false;
    result_flag = false;
   }
   if ((num.Equals(".") && textBox1.Text.IndexOf(".") < 0) || !num.Equals("."))
   {
    //如果用户输入的是小数点.，则要判断当前已输入的数字中是否含有小数点.才允许输入
    textBox1.Text += num;
    label1.Text += num;
    can_operate_flag = true;
   }
  }


  private void bt0_Click(object sender, EventArgs e)
  {
   num_down("0");
  }

  private void bt1_Click(object sender, EventArgs e)
  {
   num_down("1");
  }

  private void bt2_Click(object sender, EventArgs e)
  {
   num_down("2");
  }

  private void bt3_Click(object sender, EventArgs e)
  {
   num_down("3");
  }

  private void bt4_Click(object sender, EventArgs e)
  {
   num_down("4");
  }

  private void bt5_Click(object sender, EventArgs e)
  {
   num_down("5");
  }

  private void bt6_Click(object sender, EventArgs e)
  {
   num_down("6");
  }

  private void bt7_Click(object sender, EventArgs e)
  {
   num_down("7");
  }

  private void bt8_Click(object sender, EventArgs e)
  {
   num_down("8");
  }

  private void bt9_Click(object sender, EventArgs e)
  {
   num_down("9");
  }

  private void bt_point_Click(object sender, EventArgs e)
  {
   num_down(".");

  }

  //符号键的输入
  private void bt_plus_Click(object sender, EventArgs e)
  {
   if (!add_flag)//防止用户多次输入一个符号键，符号键只允许输入一次
   {
    result_flag = false;
    value_list.Add(double.Parse(textBox1.Text));//将当前已输入的数字放入value_list
    operator_list.Add(0);
    label1.Text += "+";
    add_flag = true;
    can_operate_flag = false;//刚刚输入完符号，不能构成一条正常的表达式，如111+，设置为不可运行状态
   }
  }

  private void bt_minus_Click(object sender, EventArgs e)
  {
   if (!minus_flag)
   {
    result_flag = false;
    value_list.Add(double.Parse(textBox1.Text));
    operator_list.Add(1);
    label1.Text += "-";
    minus_flag = true;
    can_operate_flag = false;
   }
  }

  private void bt_multi_Click(object sender, EventArgs e)
  {
   if (!multi_flag)
   {
    result_flag = false;
    value_list.Add(double.Parse(textBox1.Text));
    operator_list.Add(2);
    label1.Text = "(" + label1.Text + ")" + "×";//给前面的已经输入的东西加个括号。（运算符栈问题是一个很复杂的数据结构问题，这里不做，：P）
    multi_flag = true;
    can_operate_flag = false;
   }
  }

  private void bt_div_Click(object sender, EventArgs e)
  {
   if (!div_flag)
   {
    result_flag = false;
    value_list.Add(double.Parse(textBox1.Text));
    operator_list.Add(3);
    label1.Text = "(" + label1.Text + ")" + "÷";
    div_flag = true;
    can_operate_flag = false;
   }
  }

  private void bt_result_Click(object sender, EventArgs e)
  {

   if (value_list.Count > 0 && operator_list.Count > 0 && can_operate_flag)
   {//需要防止用户没输入数字，或者只输入了一个数，就按=。
    value_list.Add(double.Parse(textBox1.Text));
    double total = value_list[0];
    for (int i = 0; i < operator_list.Count; i++)
    {
     int _operator = operator_list[i];//operator是C#的运算符重载的关键字，前面加个_来区别
     switch (_operator)
     {
      case 0:
       total += value_list[i + 1];
       break;
      case 1:
       total -= value_list[i + 1];
       break;
      case 2:
       total *= value_list[i + 1];
       break;
      case 3:
       total /= value_list[i + 1];
       break;
     }
    }
    textBox1.Text = total + "";
    label1.Text = total + "";
    operator_list.Clear();//算完，就清空累积数字与运算数组
    value_list.Clear();
    result_flag = true;//表示=按下
   }
  }

  //CE键，将所有东西初始化
  private void btCE_Click(object sender, EventArgs e)
  {
   operator_list.Clear();
   value_list.Clear();
   add_flag = false;
   minus_flag = false;
   multi_flag = false;
   div_flag = false;
   result_flag = false;
   can_operate_flag = false;
   textBox1.Clear();
   label1.Text = "";
  }

 }
}