A small square root calculator.

SquareRoot.hx

import cpp.Lib;
 
/**
 *  A square root approximator.
 *
 *  Adapted from:
 *    http://en.wikipedia.org/wiki/Newton's_method
 *  Initial guess calculation adapted from:
 *    http://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Rough_estimation
 *
 *  This is free and unencumbered software released into the public domain.
 *  
 *  Anyone is free to copy, modify, publish, use, compile, sell, or
 *  distribute this software, either in source code form or as a compiled
 *  binary, for any purpose, commercial or non-commercial, and by any
 *  means.
 *  
 *  In jurisdictions that recognize copyright laws, the author or authors
 *  of this software dedicate any and all copyright interest in the
 *  software to the public domain. We make this dedication for the benefit
 *  of the public at large and to the detriment of our heirs and
 *  successors. We intend this dedication to be an overt act of
 *  relinquishment in perpetuity of all present and future rights to this
 *  software under copyright law.
 *  
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 *  IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
 *  OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 *  ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 *  OTHER DEALINGS IN THE SOFTWARE.
 *  
 *  For more information, please refer to <http://unlicense.org/>
 *   
 *  @author lemon42
 */
 
class SquareRoot {
	static function main() {
		var x:Float = 123456789;
		Sys.println("Square root of " + x + ": " + newton(x));
	}
	
	static function average(a:Float, b:Float):Float {
		return (a + b) / 2.0;
	}
	static function improve(guess:Float, x:Float):Float {
		return average(guess, x / guess);
	}
	
	static function newton(x:Float) {
		var guess:Float = x;
		
		//Calculate inital guess
		var val = 0;
		while (guess >= 100) {
			guess /= 10;
			val++;
		}
		
		if (guess < 10) {
			guess = 2 * Math.pow(10, Math.floor(val / 2));
		} else {
			guess = 6 * Math.pow(10, Math.floor(val / 2));
		}
			
		//Start improving estimation
		while (Math.abs(guess * guess - x) >= 0.0001)
			guess = improve(guess, x);
		
		return guess;
	}
}