Go: Newton's method of approximating square roots

newton.go

package main

import (
	"fmt"
	"math"
)

const DELTA = 0.00000001

func Sqrt(x float64) float64 {
	guess := float64(1)
	for {
		guess = guess - (guess*guess - x)/(2*guess)
		if math.Abs(x-guess*guess) <= DELTA  {
			break
		}
	}
	return guess
}

// Alternative method
// I like this one better, and I feel like it's more effecient since it removes the superflous if statement.
func SqrtAlt(x float64) float64 {
	guess, d := float64(1), float64(1)
	for d > DELTA {
		guess = guess - (guess*guess - x)/(2*guess)
		d = math.Abs(x-guess*guess)
	}
	return guess
}


func main() {
	fmt.Println(Sqrt(500))
	fmt.Println(SqrtAlt(500))
	fmt.Println(math.Sqrt(500))
}

/*
Output:

22.360679774997898
22.360679774997898
22.360679774997898
*/