A Tour of Go - Methods and Interfaces - Exercise: Errors (20/26)

exercise-errors.go

package main

import (
	"fmt"
)

type ErrNegativeSqrt float64

func (e ErrNegativeSqrt) Error() string {
	return fmt.Sprintf("cannot Sqrt negative number: %v",float64(e))
}


func Sqrt(x float64) (float64, error) {
    if x < 0 {
		return 0,ErrNegativeSqrt(x)
	}
	result := 1.0
	for count := 0 ;count < 10;count++ {
		result = result - ((result*result - x)/(2*result))
		//fmt.Println(x)
	}
	return result, nil
}

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