C#计算器

前段时间写的，计算方法是在网上找的方法，简单修改了一下，没想到期末老师布置的综合题是4道选1道，其中就有计算器，嘿嘿...
（旧博客转移自此的，原文发表时间：2008-12-20 01:46:07）

先来一张图片：

 

计算方法用到非泛型集合stack

部分代码：

按数字按钮：

 1 private void btnNum0_Click_1(object sender, EventArgs e) 
 2                 { 
 3                         if (newNum) 
 4                         { 
 5                                 txtDisplay.Text = "0."; 
 6                         } 
 7                         else 
 8                         { 
 9                                 if (pointKey) //如果小数点按钮已按，textBox原样加0 
10                                         txtDisplay.Text += "0"; 
11                                 else if (txtDisplay.Text[0] == '0' || newNum) //如果小数点未按，textBox不变，小数点启用 
12                                         txtDisplay.Text = "0."; 
13                                 else 
14                                         txtDisplay.Text= txtDisplay.Text.Insert(txtDisplay.Text.Length-1,"0"); 
15                         } 
16                         newNum = false; 
17                 }

按运算符按钮：

 1                 private void btnPlus_Click(object sender, EventArgs e) 
 2                 { 
 3                         //把displayTextBox.Text内容插入到stack的顶部，做为运算符前边的数字，和while里switch语句中的stk.Push()类似。做完stk第一个元素 
 4                         stk.Push(decimal.Parse(txtDisplay.Text)); 
 5                         while (stk.Count >= 3) 
 6                         { 
 7                                 //若stk里的元素个数为3个或以上，将最后一个运算符号之前的计算结果增加为stk的第一个元素，以实现连续计算： 
 8                                 decimal y = (decimal)stk.Pop(); 
 9                                 char sign = (char)stk.Pop(); 
10                                 decimal x = (decimal)stk.Pop(); 
11  
12                                 switch (sign) 
13                                 { 
14                                         case '+': 
15                                                 stk.Push(x + y); 
16                                                 break; 
17                                         case '-': 
18                                                 stk.Push(x - y); 
19                                                 break; 
20                                         case '*': 
21                                                 stk.Push(x * y); 
22                                                 break; 
23                                         case '/': 
24                                                 stk.Push(x / y); 
25                                                 break; 
26                                 } 
27                         } 
28                         txtDisplay.Text = stk.Peek().ToString();//返回最后一个加号之前数字的值 
29                         if (!txtDisplay.Text.Contains(".")) 
30                                 txtDisplay.Text += "."; 
31                         stk.Push('+'); //给stk增加一个运算符“+”，即stk的第二个元素 
32                         newNum = true; 
33                         pointKey = false; 
34                 }

退格按钮代码：

 1 private void btnBackspace_Click(object sender, EventArgs e) 
 2                 { 
 3                         string numString = txtDisplay.Text; 
 4                         //用到Substring()方法截取字符串来获得退格的效果 
 5                         if (numString[numString.Length - 1] == '.') //若文本框最后有小数点 
 6                         { 
 7                                 if (numString.Length != 2) //判断文本框是否已经退格到长度为2 
 8                                 { 
 9                                         //长度若不为2则删除字符串小数点前边最后一个字符，再加上小数点显示出来 
10                                         string before = numString.Substring(0, numString.Length - 2);//截取的字符串为第0个开始，长度为numString.Length - 2 
11                                         txtDisplay.Text = before + "."; 
12                                 } 
13                                 else if (numString.Length == 2) //若文本框退格到长度为2，继续退格则变为0. 
14                                 { 
15                                         txtDisplay.Text = "0."; 
16                                 } 
17                         } 
18                         else if (txtDisplay.Text.Contains(".")) //若文本框中间有小数点 
19                         { 
20                                 txtDisplay.Text = numString.Substring(0, numString.Length - 1); 
21                         } 
22  
23                 }