> I optimized it for computers.

> Professor Dr J R Stockton, Surrey, UK. optimized it also and his

runs

> twice as fast as what I had developed.

I expect that the calculations built into the C library and such which

yield day of week are similarly fast. I doubt I could beat them and

would not try.

<aside>

A month or so ago I was looking into finding the greatest common

divisor of two integers. I had a pretty crude algorithm that I had

written some years ago. After telling a colleague about it, he very

quickly pointed me in the right direction...

Euclid's algorithm, developed around 300 BC! Very very fast on a

computer.

http://aleph0.clarku.edu/~djoyce/java/elements/bookVII/propVII2.html
</aside>