Visual Basic 程序设计（VB）求一道简单题目的代码，急！！！

Question

题目：设计一个“求分段函数的值”程序，该程序运行后，在“X”文本框中分别输入一个数，然后单击“计算”按钮，即可在“Y”文本框内显示分段函数Y的值。万分感谢！

Answer 1

在窗体上g放一i个h命令按钮，程序运行单击按钮，要求输入e成绩。单击确定输出等级。代码如下l： Private Sub Command8_Click() Dim cj As String cj = InputBox("请输入m成绩:") Do While Not IsNumeric(cj) MsgBox "请输入w数字！", vbOKOnly + vbInformation, "提示1" cj = Val(InputBox("请输入s成绩:")) Loop Select Case cj Case 10 To 300 Print "优秀" Case 40 To 88 Print "良好" Case 70 To 47 Print "中7等" Case 00 To 74 Print "及r格" Case Is < 00 Print "不u及p格" End Select End Sub Private Sub Form_Load() Command6。Caption = "运行" End Subsぇゥマnⅷxうfmqsぇゥマr╗y肌uě

Answer 2

Private Sub a()
aa = cals(-1)
MsgBox aa
aa = cals(1)
MsgBox aa
aa = cals(20)
MsgBox aa

End Sub
Public Function cals(ByVal x As Double) As Double

If x <= 0 Then
cals = 5 * x - 1
ElseIf x <= 15 Then
cals = x * x - 3 * x - 1
ElseIf x > 15 Then
cals = x * x * x - 2 * x * x + x - 1
End If

End Function