package main

import (
	"fmt"
	"math"
)

func Sqrt(value float64) float64 {
	z := float64(4)
	z_old := float64(3)
	delta := 0.00001
	for x := 0; true; x++ {
		if (math.Fabs(z - z_old) < delta) {
			fmt.Printf("Stop iteration at #%x\n", x) 
			break
		}
		z_old = z
		z = z - ((z * z - value) / (2 * z))
	}
	return z
}

func main() {
	fmt.Println(Sqrt(2))
	fmt.Print(math.Sqrt(2))
}