Tour of Go Errors

sqrt_negative.go

package main

import (
	"fmt"
	"math"
)

type ErrNegativeSqrt float64

func (e ErrNegativeSqrt) Error() string {
	return fmt.Sprintf("WHAT THE FUCK IS THAT: %.0f", float64(e))

}

func Sqrt(f float64, z float64) (float64, error) {
	if f < 0 {
		return math.NaN(), ErrNegativeSqrt(f)
	}
	for i := 0; i < 10; i++ {
		z = z - (z*z-f)/(z*z)
	}
	return z, nil
}

func main() {
	fmt.Println(Sqrt(2, 1))
	fmt.Println(Sqrt(-2, 1))

}