I'm doing some error correction in Java and to cut a long story short;
Under mod 11:
-4 mod 11 = 7
This I've confirmed by using Google's calculator and a couple of online modulo calculators, but I cannot for the life of me figure out how to do it in Java.
I'm thinking that I need to use an inverse table to find the correct number but I seem to be going round in circles.
Any input would be appreciated.
Thank in advance
Tony
The following will compute n mod 11 for any integer n:
(n % 11 + 11) % 11
The result of n % 11 is in the range -10...10. The subsequent addition and the second modulo operation add 11 to n % 11 iff the latter is negative.
This formula works for any base: just replace 11 with another positive integer.