Created
November 17, 2018 02:09
-
-
Save fr-xiaoli/67b159572a8985dd866bcf5d2e2b63e9 to your computer and use it in GitHub Desktop.
A Tour of Go - Methods and interfaces - Exercise: Errors
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| 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) | |
| } | |
| z := x | |
| for i := 0; i < 10; i++ { | |
| z -= (z*z-x)/(2*z) | |
| } | |
| return z, nil | |
| } | |
| func main() { | |
| fmt.Println(Sqrt(2)) | |
| fmt.Println(Sqrt(-2)) | |
| } |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment