Sample solution for http://tour.golang.org/#24

go_tour_24.go

package main

import (
    "fmt"
    "math"
)

func Sqrt(x float64) (float64, int) {
    last := 0.0
    z := 1.0
    i := 0
    for math.Abs(last - z) > 0.0000001 {
        i++
        last = z
        z = z - ((math.Pow(z, 2) - x) / (z * 2))
    }
    return z, i
}

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