Square root calculation in Go using Newton's iteration algorithm.

square_root_newton.go

package main

import (
    "fmt"
    "math"
)

func Average(x, y float64) float64 {
    return (x + y) / 2.0
}

func Improve(guess, x float64) float64 {
    return Average(guess, x/guess)
}

func GoodEnough(guess, x float64) bool {
    d := math.Abs(guess*guess - x)
    return d < 0.0000000000001
}

func Sqrt(x float64) (guess float64, iterations int) {
    iterations = 0
    guess = 1.0
    for !GoodEnough(guess, x) {
        guess = Improve(guess, x)
        iterations += 1
    }
    return guess, iterations
}

func main() {
    //fmt.Println(Average(10, 5))
    //fmt.Println(Improve(1.0, 16))
    //fmt.Println(GoodEnough(3.5, 16))
    result, iterations := Sqrt(9)
    fmt.Println(result, iterations)
}