Go Tour: Exercise: Loops and Functions - My solution

gistfile1.go

package main

import (
	"fmt"
	"math"
)

func newtAppx(x float64, appx float64) float64 {
	return appx - ((math.Pow(appx, 2.0) - x) / (2 * appx))
}

func Sqrt(x float64) float64 {
	guess := 1.0
	appx := newtAppx(x, guess)
	
	for {
		nextAppx := newtAppx(x, appx)
		delta := math.Abs(math.Abs(nextAppx) - math.Abs(appx))

		if delta <= 0.0001 {
			break
		} else {
			appx = nextAppx
		}
	}
	
	return appx
}

func guessSqrt(x float64) {
	fmt.Println("Guess:", Sqrt(x), " Actual: ",  math.Sqrt(x))
}

func main() {
	guessSqrt(2)
	guessSqrt(54)
}