A Tour of Go - Exercise: Loops and Functions - Part 2

exercise-loops-and-functions-part-2.go

// See https://gist.github.com/bilsalak/a6016b2e564418402b1431491040f372 for part 1
//
// Next, change the loop condition to stop once the value has stopped changing 
// (or only changes by a very small amount). See if that's more or fewer than 10 iterations.
package main

import (
	"fmt"
	"math"
)

func Sqrt(x float64) float64 {
	z := 1.0
	last_z := z
	change := 1.0
	minimum_change := 0.000000000000001
	iteration := 0

	for change > minimum_change {
		z -= (z*z - x) / (2 * z)
		change = math.Abs(last_z - z)
		last_z = z
		iteration++
	}

	fmt.Println("This answer took ", iteration, " loop iterations")
	return z
}

func main() {
	for i := 1.0; i < 4; i++ {
		fmt.Println("calculating Sqrt of ", i)
		fmt.Println(Sqrt(i))
	}
}