用C#做个计算器怎么做？

Question

用C#做计算器要求：1.用double.parse()方法，将文本框中的两个数转换为double类型。           2.用switch结构进行判断。           3.用Covert.ToString() 方法将计算结果转换为字符串显示在文本框中。 

Answer 1

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Text.RegularExpressions;
namespace caculator
{
public partial class caculator1 : Form
{
String op1,op2; //定义两个操作数
bool DecimalFlag; //标识小数点是否存在
int NumOps; //记录操作数个数
String LastInput; //指示上一次按键事件的类型
int OpFlag; //指示将要进行的操作类型
bool OperaterFlag; //指示是否已经进行过操作
String TempReadout;
public caculator1()
{
InitializeComponent();//初始化界面控件
}
private void caculator1_Load(object sender, EventArgs e) //对变量进行初始化赋值
{
DecimalFlag = false; //小数点标志赋为false
OperaterFlag = false; //尚未进行过操作
NumOps = 0; //操作数个数为
LastInput = "NONE";
OpFlag = 0;
ReadOut.Text = "0."; //文本框中初始值为“.”
}
public void calculate(int MyNumber) //接收操作数
{
if (!OperaterFlag) //判断是否点击过操作符，初始值为false 如果没有点击操作符
{
if (DecimalFlag) //判断是否点击过小数点，初始值为false 如果已经点击过小数点
{
ReadOut.Text = ReadOut.Text + MyNumber; //直接把点击的数字加在框中现有数据的后面 小数点后点击的数字直接追加
}
else //未曾点击过小数点则进行如下操作
{
if (ReadOut.Text == "0.")
{
ReadOut.Text = MyNumber + "."; //如果输入框中此时为“0.”，则在输入数字的后面加上小数点，如此时输入，则显示“.”
}
Else
{
ReadOut.Text = ReadOut.Text.Substring(0, ReadOut.Text.Length - 1) + MyNumber + "."; //框中数据后面加上小数点
}
}
}
else
{
ReadOut.Text = MyNumber + "."; //点击过操作符之后，输入的数字后面仍然加个小数点（为了显示的一致性，即任何时候框中的数据都是*.）
}
// DecimalFlag = false;
OperaterFlag = false;
}
private void sign_Click(object sender, EventArgs e) //正负切换（+/-）
{
if (ReadOut.Text != "0.") //此时框中的数值不为“0.”
{
if (LastInput == "NUMS") //上次输入的数为正数
{
LastInput = "NEG"; //把LastInput置为“NEG”，表明最后一次输入的数是负数
ReadOut.Text = "-" + ReadOut.Text; //给文本框中的数值前添上“-”号
}
else if (LastInput == "NEG") //如果上次输入为负数
{
LastInput = "NUMS"; //把LastInput置为“NUMS”，表明最后一次输入的数是正数
ReadOut.Text = ReadOut.Text.Substring(1, ReadOut.Text.Length - 1); //把框中的数据最前面的符号去掉（重新变成正数）
}
else //正常情况下默认此时文本框中的数值是正数，点击+/-后，变成负数
{
LastInput = "NEG";
ReadOut.Text = "-" + ReadOut.Text;
}
}
else
{
LastInput = "NUMS"; //为“0.”时的情况
}
}
private void DecimalDot_Click(object sender, EventArgs e) //小数点（.）
{
if (OperaterFlag == true)
{
ReadOut.Text = "0.";
}
DecimalFlag = true;
}
public void StandardizationShow(String s) //规范化显示
{
if (s.IndexOf(".") == -1)
{
ReadOut.Text = s + ".";
}
else
{
ReadOut.Text=s;
}
}
private void Number0_Click(object sender, EventArgs e) //点击对应的数字键时调用方法
{
calculate(0);
}
private void Number1_Click(object sender, EventArgs e)
{
calculate(1);
}
private void Number2_Click(object sender, EventArgs e)
{
calculate(2);
}
private void Number3_Click(object sender, EventArgs e)
{
calculate(3);
}
private void Number4_Click(object sender, EventArgs e)
{
calculate(4);
}
private void Number5_Click(object sender, EventArgs e)
{
calculate(5);
}
private void Number6_Click(object sender, EventArgs e)
{
calculate(6);
}
private void Number7_Click(object sender, EventArgs e)
{
calculate(7);
}
private void Number8_Click(object sender, EventArgs e)
{
calculate(8);
}
private void Number9_Click(object sender, EventArgs e)
{
calculate(9);
}
public void OperatorCal(int MyOperator) //接收操作符
{
if(!OperaterFlag) //判断以前是否单击过操作符，避免连击操作符错误
{
NumOps = NumOps + 1;
}

switch (NumOps)
{
case 0:
OperaterFlag = true;
break;
case 1:
op1 = ReadOut.Text;
OperaterFlag = true;
break;
case 2:
op2 = ReadOut.Text;
switch (OpFlag)
{
case 1:
op1 = (Double.Parse(op1) + Double.Parse(op2)).ToString(); //加
break;
case 3:
op1 = (Double.Parse(op1) - Double.Parse(op2)).ToString(); //减
break;
case 2:
op1 = (Double.Parse(op1) * Double.Parse(op2)).ToString();//乘
break;
case 0:
if (Double.Parse(op2) == 0) //除
{
MessageBox.Show("除数不能为", "计算器");
}
else
{
try
{
op1 = (Double.Parse(op1) / Double.Parse(op2)).ToString();
}
catch (Exception e)
{
Console.WriteLine("Generic Exception Handler: {0}", e.ToString());
}
}
break;
case 4:
op1 = op2; //等
break;
}
TempReadout = op1;
this.StandardizationShow(TempReadout);
NumOps = 1;
break;
}
if(NumOps!=0)
{
OpFlag = MyOperator;
}
OperaterFlag = true;
DecimalFlag = false;
// LastInput = "NUMS";
}
private void operator1_Click(object sender, EventArgs e)
{
OperatorCal(1);
}
private void operator3_Click(object sender, EventArgs e)
{
OperatorCal(3);
}
private void operator2_Click(object sender, EventArgs e)
{
OperatorCal(2);
}
private void operator0_Click(object sender, EventArgs e)
{
OperatorCal(0);
}
private void operator4_Click(object sender, EventArgs e)
{
OperatorCal(4);
}
private void Percent_Click(object sender, EventArgs e) //%
{
ReadOut.Text = (Double.Parse(ReadOut.Text) / 100).ToString();
NumOps = NumOps + 1;
DecimalFlag = true;
}
private void Cancel_Click(object sender, EventArgs e) //C
{
ReadOut.Text = "0.";
op1 = "";
op2 = "";
caculator1_Load(this, new System.EventArgs());
}
private void CancelEntry_Click(object sender, EventArgs e) //CE
{
ReadOut.Text = "0.";
DecimalFlag = false;
LastInput = "CE";
}
private void reciprocal_Click(object sender, EventArgs e) //求倒数（/x）
{
ReadOut.Text = (1/Double.Parse(ReadOut.Text)).ToString();
}
private void Copy_Click(object sender, EventArgs e) //复制
{
if(ReadOut.Text.Equals(""))
{
return;
}
Clipboard.SetDataObject(ReadOut.Text,true);
}
private void paste_Click(object sender, EventArgs e) //粘贴
{
if (Clipboard.GetDataObject().GetDataPresent(DataFormats.Text))
{
this.paste.Enabled = true;
ReadOut.Text = "";
this.ReadOut.Paste();
}
else
{
this.paste.Enabled = false;
}
}
private void Delete_Click(object sender, EventArgs e) //删除（BackSpace）
{
if (ReadOut.Text != "0.")
{
try
{
ReadOut.Text = ReadOut.Text.Substring(0, ReadOut.Text.Length - 2) + ".";
}
catch (Exception ex)
{
Console.WriteLine("Generic Exception Handler: {0}", ex.ToString());
}

if(ReadOut.Text==".")
{
ReadOut.Text = "0.";
}
}

}
private void sqrt_Click(object sender, EventArgs e)
{
TempReadout = this.ReadOut.Text;
this.ReadOut.Text = System.Convert.ToString(Math.Sqrt(System.Convert.ToDouble(TempReadout)));
}
}
}

Answer 2

double num1=Convert.ToDouble(this.textBox1.text);
double num2=Convert.ToDouble(this.textBox2.text);
double Sum=0.0；结果
string fuhao=……获得输入的符号；
……
switch（fuhao）
{
case "+": 加计算；break；//将结果赋值给sum
case "-": 减计算；break；
……
}
this.textbox3.text=sum.tostring();//显示结果

大致就这样，自己再改一下
纯手打，请采纳本回答被提问者采纳