Private LoggedIn$ As String = ""
Private LoggedAsAdmin$ As String = ""

Do
  Print "Enter username:"
  Private UserName$: Line Input UserName$

  Print "Enter password:"
  Private Password$: Line Input Password$

  Call Login(UserName$, Password$)
  Call IsLoggedIn(LoggedIn$)
  Call IsLoggedAsAdmin(LoggedAsAdmin$)
  Print LoggedIn$
  Print LoggedAsAdmin$

  If LoggedIn$ = "User logged in" Then
  Do
      FgCol = Cyan
      Print "Type an expression (H for help),"
      Print "and press Enter: " ;
      FgCol = BrightYellow
      Private Expression$ : Line Input Expression$
      Expression$ = Trim$ (Expression$)
      FgCol = BrightWhite
      Select Case UCase$ (Expression$)

      Case "", "Q": Exit

      Case "LO"
          Call Logout()
          Call IsLoggedIn(LoggedIn$)
          Call IsLoggedAsAdmin(LoggedAsAdmin$)

      Case "CP"
        If LoggedAsAdmin$ = "User logged as admin" Then
          Print "Enter username of the user to change password:"
          Private ChangedUserName$: Line Input ChangedUserName$

          Print "Enter new password:"
          Private ChangedPassword$: Line Input ChangedPassword$

          Call Password(ChangedUserName$, ChangedPassword$)
        Else
          Print "You need to be an admin to change passwords!"
        End If

      Case "T": Call TestExpressions()

      Case "H"
          Print "LO to log out"
          Print "CP to change password of a user"
          Print "Q (or just Enter) to Quit"
          Print "T to send test commands"

      Case Else
          Private Result$ : Result$ = Expression$
          Call Calculator (Result$)
          If SW1 = sw1PCodeError Then
            Select Case SW2
              Case SyntaxError: Print "Syntax error"
              Case ParenthesisMismatch: Print "Parenthesis mismatch"
              Case InvalidNumber: Print "Invalid number"
              Case Else: Call CheckSW1SW2()
            End Select
          Else
            Call CheckSW1SW2()
            Print Expression$ " = " Result$
          End If
      End Select
  Loop While LoggedIn$ = "User logged in"
  End If
Loop