newton.go

package main

import (
    "fmt"
    "math"
)

func Sqrt(x float64) float64 {
    z := x
    delta := 0.00000000001
    notDone := true
    fmt.Println("foo")
    for notDone {
        res := z - ((z*z) - x)/(2*z)
        fmt.Println(res)
        if math.Abs(res - z) < delta {
            notDone = false
        }
        z = res
    }
    return z
}

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

pointers.go

// http://tour.golang.org/#26
package main

import "fmt"

type Vertex struct {
    X int
    Y int
}

func main() {
    p := Vertex{1, 2}
    // struct is copied
    q := p
    q.X = 1e9
    fmt.Println(p)
    fmt.Println(q)
    // q2 points to struct p
    q2 := &p
    q2.X = 1e9
    fmt.Println(p)
}

http://tour.golang.org/#23

http://tour.golang.org/#28 provides knowledge about pointers to structs