Created
August 28, 2013 21:56
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A Tour of Go - Exercise: Errors
http://tour.golang.org/#56
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package main | |
import ( | |
"fmt" | |
"math" | |
) | |
type ErrNegativeSqrt float64 | |
func (e ErrNegativeSqrt) Error() string { | |
return fmt.Sprintf("cannot Sqrt negative number: %f", e) | |
} | |
const e = 1e-8 // small delta | |
func Sqrt(x float64) (float64, error) { | |
if x < 0 { | |
return 0, ErrNegativeSqrt(x) | |
} | |
z := x // starting point | |
for { | |
new_z := z - ((z*z - x) / (2*z)) | |
if math.Abs(new_z - z) < e { | |
return new_z, nil | |
} | |
z = new_z | |
} | |
} | |
func main() { | |
fmt.Println(Sqrt(2)) | |
fmt.Println(Sqrt(-2)) | |
} |
alkstsgv
commented
Aug 24, 2023
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