Question

vb利用循环结构编程计算表达式1+1/2+1/3+.....+1/n的值

要求：窗体上添加一个文本框，一个命令按钮
2，文本框可显示但不可编辑
3，命令按钮command1显示内容为“计算”，格式宋体，加粗，二号字
4，按“计算”按钮，调用inputbox函数输入n，计算表达式，按钮caption属性改为“显示
5，按“显示”按钮，在text1中显示计算结果，按钮caption属性在改为“计算”，可重复执行“计算”操作

Answer 1

Private Sub Command1_Click()

  Static n As Long, valSum As Double

  Select Case Command1.Caption

    Case "计算"

      valSum = 0

      Dim i As Long

      n = InputBox("Pleace input integer n:", "InputBox", 10)

      Command1.Caption = "显示"

      For i = 1 To n

        valSum = valSum + 1 / i

      Next i

    Case "显示"

      Label1.Caption = "n=" + CStr(n)

      Text1.Text = valSum

      Command1.Caption = "计算"

    End Select

End Sub

Private Sub Form_Load()

  Text1.Enabled = False

  Text1.Text = ""

  Command1.Caption = "计算"

  Command1.FontBold = True

  Command1.FontSize = 22

  Command1.FontName = "宋体"

  Text1.FontName = "Times New Roman"

  Text1.FontBold = True

  Text1.FontSize = 22

End Sub