讲四则运算计算器二.ppt

第三讲 四则运算计算器（二）,教育部“十二五”职业教育国家规划教材,Visual C#程序设计与软件项目实训电子工业出版社 郑伟 谭恒松 编著,ISBN:9787121246128,教材网站：/visualc/,目录,任务：设计复杂四则运算计算器,任务：功能拓展,任务：设计复杂四则运算计算器,任务：设计复杂四则运算计算器代码,1首先定义窗体的公共变量 string str, opp, opp1; double num1, num2, result; 2编写数字键的单击事件，数字键“0-9”的事件都是一个 private void number(object sender, EventArgs e) Button b = (Button)(sender);/实例化按钮对象 str = b.Text; if (txtOutput.Text = “0“)/判断是否按下为0的按钮 txtOutput.Text = str; else txtOutput.Text = txtOutput.Text + str; ,任务：设计复杂四则运算计算器代码,3编写“+、-、*、/、=”操作符键的单击事件 private void operator1(object sender, EventArgs e) Button b = (Button)(sender);/实例化按钮对象 if (b.Text = “+“)/判断是否按下加号 num1 = double.Parse(txtOutput.Text); txtOutput.Text = “; opp = “+“; opp1 = “; else if (b.Text = “-“)/判断是否按下减号 num1 = double.Parse(txtOutput.Text); txtOutput.Text = “; opp = “-“; opp1 = “; ,任务：设计复杂四则运算计算器代码,else if (b.Text = “*“)/判断是否按下乘号 num1 = double.Parse(txtOutput.Text); txtOutput.Text = “; opp = “*“; opp1 = “; else if (b.Text = “/“)/判断是否按下除号 num1 = double.Parse(txtOutput.Text); txtOutput.Text = “; opp = “/“; opp1 = “; ,任务：设计复杂四则运算计算器代码,else if (b.Text = “=“)/判断是否按下等号 if (opp1 != “=“) num2 = double.Parse(txtOutput.Text); if (opp = “+“) num1 = num1 + num2; txtOutput.Text = “ + num1.ToString(); else if (opp = “-“) num1 = num1 - num2; txtOutput.Text = “ + num1.ToString(); ,任务：设计复杂四则运算计算器代码,else if (opp = “*“) num1 = num1 * num2; txtOutput.Text = “ + num1.ToString(); else if (opp = “/“) if (num2 = 0)/判断第二个数是否为零 txtOutput.Text = “除数不能为零“; else num1 = num1 / num2; txtOutput.Text = “ + num1.ToString(); opp1 = “=“; ,任务：设计复杂四则运算计算器代码,4编写操作符键“退格-、CE、C、sqrt、%、1/x、+/-、.”等按钮的单击事件 private void operator2(object sender, EventArgs e) Button b = (Button)(sender);/实例化按钮对象 if (b.Text = “.“)/判断是否按下点 str = txtOutput.Text; int index = str.IndexOf(“.“); if (index = -1) txtOutput.Text = str + “.“; ,任务：设计复杂四则运算计算器代码,else if (b.Text = “退格-“)/判断是否按下退格符 if (txtOutput.Text != “) str = txtOutput.Text; str = str.Substring(0, str.Length - 1); txtOutput.Text = str; else if (b.Text = “CE“)/判断是否按下CE txtOutput.Text = “0“; ,任务：设计复杂四则运算计算器代码,else if (b.Text = “C“)/判断是否按下C result = num1 = num2 = 0; str = null; opp = null; txtOutput.Text = “0“; else if (b.Text = “sqrt“)/判断是否按下sqrt num1 = double.Parse(txtOutput.Text); result = Math.Sqrt(num1); txtOutput.Text = result.ToString(); ,任务：设计复杂四则运算计算器代码,else if (b.Text = “1/x“)/判断是否按下1/x num1 = double.Parse(txtOutput.Text); result = 1 / num1; txtOutput.Text = result.ToString(); else if (b.Text = “%“)/判