sqrt.go

package main

import (
	"fmt"
	"math"
)

func sqrt_newton(x float64) float64 {
	z, prev := 1.0, 3.0
	const threshold = 1e-15
	for {
		z -= (z*z - x) / (2*z)
		if math.Abs(z-prev) < threshold {
			return z
		}
		fmt.Printf("rest: %g\n", math.Abs(z-prev))
		prev = z
	}
}

func main() {
	fmt.Printf("result: %#v\n", sqrt_newton(2))
}