vb程序编写

编写程序：随机产生长度为1~20的大写字符串，并通过输入框输入一大写字母，统计该字母在大写字符串中出现的次数

Private Sub Command1_Click()

  Randomize

  Text1.Text = ""

  n = Int(Rnd * 20) + 1

  For i = 1 To n

    Text1.Text = Text1.Text & Chr(Int(Rnd * 26 + 65))

  Next i

End Sub

Private Sub Command2_Click()

  c = InputBox("请输入一个大写字母：")

  n = 0

  For i = 1 To Len(Text1.Text)

    If Mid(Text1.Text, i, 1) = c Then n = n + 1

  Next i

  MsgBox Text1.Text & " 中有 " & n & " 个 " & c

End Sub

Private Sub Form_Load()

  Text1.Text = ""

End Sub