填空题

下列程序实现的功能是：当在窗体上单击时，将输出a1．txt 文件中的数字字符的个数。Private Sub form_ Click() Dim Ch As String * 1 Dim n As Integer Open "c:\\a1. txt" for Input As #10 do while Ch = Input(1, #10) if then n=n+1 End if Loop Close #10End Sub