My father would always scold me that so many applications are open when he turns on the computer which he says consumes computer memory. I always forget to close the app by right -clicking>quit Is there any way to automatically close an app when shutting down? When I searched at google. They talked about iCalendar, but it was too confusing so I came here to ask.
Basically all apps will be closed when shutting down, simply because the computer will be turned off. Just to be sure: Shutting down means: Turning the computer off.
However the behavior after rebooting differs depending on the operation system version you are using. If you are running Lion or Mountain Lion there is a feature that allows to automatically restart all open applications after rebooting/start up. In Mountain Lion you will be asked before the computer shuts down if you want the applications to be restarted after reboot. Just uncheck the checkbox.
If you're confusing shutting down with standby and/or sleep mode you will have no built-in way to solve it (but an AppleScript may help). But at least I can provide you with a shortcut: Pressing ⌘ Command Q will "completely" close an application. You can use this shortcut instead of right clicking the dock icon to close the app.
If you are using mac os x lion or later, which you apparently do, you can just uncheck the "reopen windows when logging back in" when the log-out or shut down menu comes up!
This way your perviously opened app won't open again!
If they do... you have certain applications set as a* login item this is fixed by opening system pref - users & groups - login items and review that list.