Question

vb问题。用select case语句方法写出分段函数？

Answer 1

Private Sub Command1_Click()
Dim x As Integer, y As Double
x = Val(InputBox("enter data x:"))
Select Case x
Case Is > 20
y = x ^ 2 + 3 * x + 2
Case Is >= 10 And x <= 20
y = Sqr(3 * x) - 2
Case Is > 0 And x < 10
y = 1 / x + Abs(x)
End Select
Print Format(y, "#.0000")
End Sub

追问

书不说case句子不能出现逻辑等运算符和表达式中的变量，那case is>0 and x<10不说不符合他规定了嘛？

追答

简单的可以，我测试了的，没问题！

追问

那书上这么写是不是错了，如果要表达分段函数，必定要出现and or 这些东西的呀

追答

不好意思，我改了一下！
Private Sub Command1_Click()
Dim x As Integer, y As Double
x = Val(InputBox("enter data x:"))
Select Case x
Case Is > 20
y = x ^ 2 + 3 * x + 2
Case 10 to 20
y = Sqr(3 * x) - 2
Case 0 to 9
y = 1 / x + Abs(x)
End Select
Print Format(y, "#.0000")
End Sub