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 = "";    }  }}