Recently I needed to calculate the distance between two points. Not too difficult by itself, all you need is the square root of the X/Y distances:
sqrt( (x1 - x2) * (x1-x2) + (y1 - y2) * (y1 - y2) )
Thing is: CLDC 1.0 does not have a sqrt function, only CLDC 1.1 has… Plus, double and float are also both CLDC 1.1 - which is OK, since I only needed an integer value.
Wikipedia proved to be a good source of information, once more, so I found that I could implement the Newton Method to achieve the desired result. Since I had no luck finding appropriate code with Google that I could employ, I wrote the function myself. See code below.
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This post is more for my own benefit than for the public out there. Whenever I do some coding (rarely, which is part of the problem) I come across a problem and, after some trying & researching, possibly a solution.
However, after some time this solution is lost in the depths of my source codes. And a new research is sometimes futile - plus I reject the notion of going through the hoops again, since I already should know what to do. So, now I’ll drop little code nuggets here, so I can find them again with less effort. It’s certainly not an entertaining post, but it helps me.
First item: toggling boolean variables
I like to work with boolean values, and sometime I need to toggle them. So a true becomes false and vice versa. Of course this should be a short oneliner. Not an if-else construct. A good approach is:
boolean = boolean ? false : true;
I tend to use the ?: operator ad nauseum… so an even better approach is (and my preferred way to do it):
boolean ^= true;
What is this? A XOR assignment operator, similar to += or -= If boolean is true, then the XOR return false (because it is not an inclusive OR). If boolean is false, then the XOR returns true. Mission accomplished.
