VBA : InputBox wrongly used previous User Input without prompting for new input - vba

Question

This is the VBA code I am learning to write (got some reference from the Internet)
Public whatyousay As String
Sub testing()
b14
b15
End Sub
Function WorksheetExists(WSName As String) As Boolean
On Error Resume Next
WorksheetExists = Worksheets(WSName).Name = WSName
On Error GoTo 0
End Function
Sub b14()
Dim sh As Worksheet
Do Until WorksheetExists(whatyousay)
whatyousay = InputBox("Enter sheet name")
If Not WorksheetExists(whatyousay) Then MsgBox whatyousay & " doesn't exist.", vbExclamation
Loop
If WorksheetExists(whatyousay) Then Sheets(whatyousay).Activate
End Sub
Sub b15()
ThisWorkbook.Worksheets(whatyousay).Range("A1").Value = xxxx
End Sub
I must have wrongly adjust the code, as I can't find anyone having the same problem on the Internet.
When the button is clicked, it is supposed to prompt user input for the sheet name, then perform some actions.
Now, the problem I am facing is that the button only prompt user input for one time. If it was clicked the second time, it will used the previous user input without prompting.
Can anyone of you please point me to the right direction?

Answer 1

You are not erasing what was left in whatyousay during the last loop.
Sub b15()
ThisWorkbook.Worksheets(whatyousay).Range("A1").Value = xxxx
whatyousay = vbnullstring '<~~ remove the string from last time
End Sub
Personally, I avoid public vars. You can do the same thing by passing the string var into the secondary sub as a parameter.