Excel 2013: How To Check How Many Excel Files Are Open

[peccora3]

Thank you for your quick answer.
Your script works fine in Excel vba.
Now, I need to run this script from Powerpoint, and either of the scripts returns 0.

Following is what I have written for your first answer:
(I have Microsoft Excel 15.0 Object Library checked on Reference and a few Excel files open prior to running the script)

Dim exl as Excel.Application
Dim wbct as integer
Set exl = New Excel.Application
exl.Visible = True
wbct = exl.Application.Workbooks.Count  '<=  wbct returns 0

Your second answer returned the same.

What am I doing wrong?