ex_loop_and_functions.go

package main

import (
	"fmt"
	"math"
)

func Sqrt(x float64) float64 {
	z := 1.0
	for {
		old := z
		z = z - ((z*z - x) / 2 * z)
		if diff := math.Abs(old - z); diff < 0.0001 {
			return z
		}
	}
}

func main() {
	fmt.Println("newton: ", Sqrt(2))
	fmt.Println("math: ", math.Sqrt(2))
	fmt.Println("diff:", math.Sqrt(2)-Sqrt(2))
}