I'm trying to create an app for a workshop that I'll be running as an "Introduction to Objective-C for developers".

It's going to be a variation of the temperature converter app that tends to be the "Introduction to programming" default.

Anyway, I was wondering about conversions.

If you take, temperature, time, pressure, distance... and the rest of the categories from this site... http://www.digitaldutch.com/unitconvert ... urrent.htm

Do all the conversions follow the pattern... y = mx + c (i.e. the formula of a straight line).

Can you give me an example that doesn't use this calculation? I can't think of one. In fact, with the exception of fahrenheit, most of them are just y = mx.

Is that correct?

There are some more difficult ones such as light and sound which have units which are not directly convertible, but otherwise yes you're right.

Oh, there's also hardness and things like wind speed. They have non-linear scales too.

Cool thanks.

And sound. I think that they are all logarithmic in scale.