We’ve decided to do it again. After the success of the Functional Programming eXchange 2011 and 2009, we have decided to put on another edition. Functional Programming eXchange 2012 will take place on Friday March 16th March 2012, at the Skills Matter eXchange, in London. The program is under construction, I’ve already started to invite speakers whose work in the functional programming community interests and excites me. I’m actively seeking other speakers so if you’d be interested in following in the foo[...]

Problem Each character on a computer is assigned a unique code and the preferred standard is ASCII (American Standard Code for Information Interchange). For example, uppercase A = 65, asterisk (*) = 42, and lowercase k = 107. A modern encryption method is to take a text file, convert the bytes to ASCII, then XOR [...]

Problem A common security method used for online banking is to ask the user for three random characters from a passcode. For example, if the passcode was 531278, they may ask for the 2nd, 3rd, and 5th characters; the expected reply would be: 317. The text file, keylog.txt, contains fifty successful login attempts. Given that [...]

Problem Some positive integers n have the property that the sum [ n + reverse(n) ] consists entirely of odd (decimal) digits. For instance, 36 + 63 = 99 and 409 + 904 = 1313. We will call such numbersreversible; so 36, 63, 409, and 904 are reversible. Leading zeroes are not allowed in either [...]

Problem The number 145 is well known for the property that the sum of the factorial of its digits is equal to 145: 1! + 4! + 5! = 1 + 24 + 120 = 145 Perhaps less well known is 169, in that it produces the longest chain of numbers that link back to [...]