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@jonpaul
Last active December 15, 2015 04:49
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Go Tour Exercises
package main
import (
"fmt"
"math"
)
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, result := 2.0, 0.0
for {
z = z - (z * z - x) / (2 * z)
if math.Abs(result-z) < 1e-15 {
break
}
result = z
}
return result, nil
}
func main() {
fmt.Println(Sqrt(2))
fmt.Println(Sqrt(-2))
}
package main
import (
"fmt"
"math"
)
func Sqrt(x float64) float64 {
z, result := 2.0, 0.0
for {
z = z - (z * z - x) / (2 * z)
if math.Abs(result-z) < 1e-15 {
break
}
result = z
}
return result
}
func main() {
fmt.Println(Sqrt(2))
fmt.Println(math.Sqrt(2))
}
package main
import (
"code.google.com/p/go-tour/wc"
"fmt"
"strings"
)
func WordCount(s string) map[string]int {
fields := strings.Fields(s)
ret := make(map[string]int, len(fields))
for _, s := range fields {
fmt.Println(s)
ret[s] += 1
}
return ret
}
func main() {
wc.Test(WordCount)
}
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