A Tour of Go. Advanced Exercise: Complex cube roots.

cbrt.go

package main

import (
  	"fmt"
	"math"
)

func Cbrt(x complex128) complex128 {
	next := func(z complex128) (complex128, float64) {	//takes the result of the last iteration, and returns new result and difference
		newz := z - (((z * z * z) - x) / (3 * (z * z)))
		diff := math.Abs(real(z - newz))
		return newz, diff
	}

	newz, diff := next(x)
	for diff > 0.00001 {
		fmt.Println(newz) // Optional to print out each iteration
		newz, diff = next(newz)
	}
	return newz

}

func main() {
	fmt.Println(Cbrt(2))
}