Perl script reveals math trick
MIND GAMES
A trick that anybody can learn lets you determine the day of the week from the date. We’ll apply some Perl technology to discover whether the method is reliable.
Recently, I was reading Mind Performance Hacks and stumbled across Hack Number 43, which explains how to determine the day of the week for any given date. The method is attributed to Lewis Carroll], the author of Alice’s Adventures in Wonderland. Simply calculate four values, one after the other, for the year, month, and day, and a fourth value as an adjustment factor. Then add the values, divide by 7, and the remainder amazingly gives you the day of the week as a number between zero (Sunday) and six (Saturday).
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
US / Canada
UK / Australia
News
-
Cisco Releases Annual Security Report
Spammers go low-volume, and 90% of IE browsers are unpatched.
-
Zero Day Exploits Target Flash
Adobe scrambles to release patches for vulnerable Flash Player.
-
Intel Unveils Compute Stick
Four-inch-long computer on a stick lets you boot a full Linux system from any HDMI display device.
-
Obama Proposes Personal Data Notification Law
New statute would require companies to report break-ins to consumers.
-
TGXf Project Warns of File Transfer through Screen Pixels
Weird data transfer technique avoids all standard security measures.
-
Industry Giants Announce a Fix for the Password Mess
FIDO alliance declares the beginning of the end for old-style login authentication.
-
Poll: Vote for the Best Open Source Software for Photographers
The Linux New Media Awards have honored the most significant products, projects, people, and organizations for open source/Linux every year since 2000.
-
Debian Gets Forked
Legendary Uber-distro splits over the systemd controversy.
-
Linux Mint Project Releases Mint 17.1
New LTS version offers many refinements for the Cinnamon and Mate desktops and significant improvement under the hood.
-
CeBIT Open Source Forum Call for Papers
One of CeBIT’s most successful forums returns in 2015.