Rudolf,
CRC Handbook (ha), or try [url]
www.metric-conversions.org
[/url]
You may end up using a lot of unit conversions, and some of them will be "unusual". As in rarely used by most technologists. You may even have to figure out the values for some of them yourself.
I'd set up a bunch of constants for this.
example -
some common conversion factors
CONST SecondsPerMinute = 60
CONST SecondsPerHour = 60 * SecondsPerMinute
CONST SecondsPerDay = 24 * SecondsPerHour
CONST KilometersPerAU = 149598000000
(I like to avoid abreviations, but that's just a personal style issue. You can (and should) get pretty fancy here. Use previous definitions to help build new ones. I always use constants and variables instead of numbers. Some compilers claim the code is faster if you avoid actual hard coded numbers.)
Then all you have to remember is the name of the constant. This has the added benefit of making the code more readable, and reducing the need to add (and maintain) comments.
The only down side is some rather long names if you don't abreviate severely. But abreviations can haunt you six months later.
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<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">
[Rudolf] How would I have to adjust G for say the following combinations:
Kilometer and second
Astronomical unit and day
Lightyear and year<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
G is 6.67300 m^3 / (kg * sec^2) using mks units, so
CONST G_mks = 6.673
to get this in units of lightyears, kilograms and years per your third example, do the conversion in several steps. First meters to Ly
CONST G_Lyks = G_mks * LightYearsPerMeter^3
Next seconds to years
CONST G_LykY = G_Lyks * YearsPerSecond^2
You could of course also convert the kilograms into another unit with one more pass.
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Keeping your units straight is very important. Any time you add a new constant, be very methodical about it.
Regards,
LB
