SquareRoot.hx

package ;

import cpp.Lib;
import haxe.Int64;

/**
 * A square root approximator.
 * 
 * @author lemon42
 */

class Main 
{
	static var acc:Float = 0.00001;
	
	
	static function main() {
		var x:Float = 7777777777;
		Sys.println("Square root of " + x);
		Sys.println("Accuracy: " + acc);
		Sys.println("");
		
		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 check(guess:Float, x:Float):Bool {
		return Math.abs(guess * guess - x) < acc;
	}
	
	static function newton(x:Float) {
		var i = 0;
		var guess:Float = x;
		var start:Float = Sys.time();
		
		//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 (!check(guess, x)) {
			Sys.println("  Guess " + ++i + " --> " + guess);
			guess = improve(guess, x);
		}
		Sys.println("  Guess " + ++i + " --> " + guess);
		
		Sys.println("");
		Sys.println("Guessed in " + i + " tries, " + (Sys.time() - start) + " secs");
		Sys.println("");
		
		return guess;
	}
}