"大学计算机VB程序设计考试题目：四则运算窗体设计与代码"

实验三第 1 题要求设计一个窗体，其中包括五个命令按钮，分别用于完成加、减、乘、除四则运算以及退出程序的功能。在计算除法时，假如第二个数是零，则需要在消息框中显示信息“除数为零”。具体的代码如下： Public Class Form1 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim a, b As Single a = TextBox1.Text b = TextBox2.Text TextBox3.Text = a + b End Sub Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click Dim a, b As Single a = TextBox1.Text b = TextBox2.Text TextBox3.Text = a - b End Sub Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click Dim a, b As Single a = TextBox1.Text b = TextBox2.Text TextBox3.Text = a * b End Sub Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click Dim a, b As Single a = TextBox1.Text b = TextBox2.Text If b = 0 Then MessageBox.Show("除数为零") Else TextBox3.Text = a / b End If End Sub Private Sub Button5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button5.Click Me.Close() End Sub End Class 以上代码实现了四则运算功能，并且在计算除法时考虑了除数为零的情况。通过设计并编写这段代码，可以实现基本的数学运算功能，并且在出现异常情况时进行相应的处理，提高了程序的鲁棒性和稳定性。