女戒烟多久可以怀孕:为什么计算机程序都是这样的?请问计算机怎么去执行这种样的代码?

Option Explicit
Dim sz As Integer ＆#39;用来记录进行何种运算
Dim x As Single, y As Single ＆#39;用来记录进行运算的两个数
＆#39;从第一个命令按钮到第十个是用来输入0至9十个数字的
Private Sub Command1_Click()
Text1.Text = Text1.Text & "1"
End Sub
Private Sub Command2_Click()
Text1.Text = Text1.Text & "2"
End Sub
Private Sub Command3_Click()
Text1.Text = Text1.Text & "3"
End Sub
Private Sub Command4_Click()
Text1.Text = Text1.Text & "4"
End Sub
Private Sub Command5_Click()
Text1.Text = Text1.Text & "5"
End Sub
Private Sub Command6_Click()
Text1.Text = Text1.Text & "6"
End Sub
Private Sub Command7_Click()
Text1.Text = Text1.Text & "7"
End Sub
Private Sub Command8_Click()
Text1.Text = Text1.Text & "8"
End Sub
Private Sub Command9_Click()
Text1.Text = Text1.Text & "9"
End Sub
Private Sub Command10_Click()
Text1.Text = Text1.Text & "0"
End Sub
Private Sub Command11_Click()
Text1.Text = Text1.Text & "." ＆#39;输入小数点
End Sub
Private Sub Command12_Click()
x = CSng(Text1.Text) ＆#39;将输入的数转换成单精度型的
sz = 1 ＆#39;设置即将进行的是加法运算
Text1.Text = "" ＆#39;将文本框清空，以便输入第二个数
End Sub
Private Sub Command13_Click()
x = CSng(Text1.Text)
sz = 2
Text1.Text = ""
End Sub
Private Sub Command14_Click()
x = CSng(Text1.Text)
sz = 3
Text1.Text = ""
End Sub
Private Sub Command15_Click()
x = CSng(Text1.Text)
sz = 4
Text1.Text = ""
End Sub
Private Sub Command16_Click()
x = CSng(Text1.Text)
sz = 5
Text1.Text = ""
End Sub
Private Sub Command17_Click()
x = CSng(Text1.Text)
Text1.Text = Sqr(x) ＆#39;因为求平方根只需一个运算对象，因此在此就给出结果
End Sub
Private Sub Command18_Click()
On Error GoTo ex ＆#39;设置如果遇到错误就退出此过程
y = CSng(Text1.Text)
Select Case sz ＆#39;根据sz的值来决定进行何种运算
Case 1
Text1.Text = x + y ＆#39;进行加法运算并将结果显示在文本框中
Case 2
Text1.Text = x - y
Case 3
Text1.Text = x * y
Case 4
Text1.Text = x / y
Case 5
Text1.Text = x Mod y
End Select
ex:
End Sub
Private Sub Command19_Click()
Text1.Text = "" ＆#39;将文本框清空，以便输入新的数字
End Sub