mainly by using for-range loops but also by simplifying some simple algo

Change-Id: If5ce6d901761db2b872a99e6de0eb6d2f098df99
Reviewed-on: https://gerrit.libreoffice.org/51044Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Julien Nabet <serval2412@yahoo.fr>