./ex-application [-b] [-h] [--log-file=file] [--log-level=string] [--string=any_string] more_string...

	-b	Sample boolean argument.
	-h, --help	Print this help screen.
	--log-file	The file to use to store log informations.
	--log-level	Level of log informations:
		error: error messages,
		warning: warning and error messages,
		verbose: all messages.
	--string	Print a string.
Testing error_level:
Testing warning_level:
Testing verbose_level:
'-b' argument is missing.
'--string' argument value is ''
./ex-application [-b] [-h] [--log-file=file] [--log-level=string] [--string=any_string] more_string...

	-b	Sample boolean argument.
	-h, --help	Print this help screen.
	--log-file	The file to use to store log informations.
	--log-level	Level of log informations:
		error: error messages,
		warning: warning and error messages,
		verbose: all messages.
	--string	Print a string.
Testing error_level:
Testing warning_level:
Testing verbose_level:
'-b' argument is missing.
'--string' argument value is ''
