gotour

cube_root.go

package main
 
import (
	"fmt"
	"math/cmplx"
)
 
func Cbrt(x complex128) complex128 {
	z := complex128(2)
	s := complex128(0)
	for {
		z = z - (cmplx.Pow(z,3) - x)/(3 * (z * z))
		if cmplx.Abs(s-z) < 1e-17 {
			break
		}
		s = z
	}
	return z
}
 
func main() {
	fmt.Println(Cbrt(8))
}
 

error_negative_sqrt.go

package main

import (
    "fmt"
    "math"
)

type ErrNegativeSqrt float64

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

func Sqrt(f float64) (float64, error) {
    if f < 0 {
    	return float64(0), ErrNegativeSqrt(f)    
    }
    return math.Sqrt(f), nil
}

func main() {
    fmt.Println(Sqrt(4))
    fmt.Println(Sqrt(-2))
}

fibonacci.go

package main

import "fmt"

// fibonacci is a function that returns
// a function that returns an int.
func fibonacci() func() int {
    a := 0
    b := 1
    return func() int {
        a, b = b, a + b
        return a
    }
}

func main() {
    f := fibonacci()
    for i := 0; i < 10; i++ {
        fmt.Println(f())
    }
}

word_count.go

package main

import (
    "code.google.com/p/go-tour/wc"
    "strings"
)

func WordCount(s string) map[string]int {
    m := make(map[string]int)

    for _, word := range strings.Fields(s) {
        m[word] += 1
    }

    return m
}

func main() {
    wc.Test(WordCount)
}