Tour of Go

ToG25.go

package main
 
import (
    "fmt"
)
 
func Sqrt(x float64) float64 {
    z:= x
    for i:=0;i<10000;i++ {
        z=z-(z*z-x)/(2*z)
    }
    return z
}
 
func main() {
    fmt.Println(Sqrt(2))
}

ToG38.go

package main
 
import "code.google.com/p/go-tour/pic"


func Exp(x, y int) int{
    return x^y
}
func Pic(dx, dy int) [][]uint8 {
    y := make([][]uint8, dy)
    for i := range y {
        y[i] = make([]uint8, dx)
        for j:=range y[i] {
            y[i][j] = uint8(Exp(i,j))
        }
    }
    return y
}
 
func main() {
    pic.Show(Pic)
}

ToG43.go

package main
 
import (
    "code.google.com/p/go-tour/wc"
    "strings"
)
 
func WordCount(s string) map[string]int {
    
    words := make(map[string]int)
    wl := strings.Fields(s)
    
    for i := range wl {
        ele := words[wl[i]]
        words[wl[i]] = ele+1
    }
    return words
}
 
func main() {
    wc.Test(WordCount)
}

ToG50.go

package main
 
import "fmt"
 
func Cbrt(x complex128) complex128 {
    
    z:= x
    
    for i := 0;i<100000;i++ {
        z=z-((z*z*z-x)/(3*z*z))
    }
    return z
}
 
func main() {
    fmt.Println(Cbrt(2))
}

Tog58.go

package main
 
import (
    "fmt"
)
 
type ErrNegativeSqrt float64
 
func (e ErrNegativeSqrt) Error() string {
    return fmt.Sprintf("cannot Sqrt negative number: %f", float64(e))
}
 
func Sqrt(f float64) (float64, error) {
    z:=f
    if f<0 {
        return f, ErrNegativeSqrt(f)
    }
    for i:=0;i<100000;i++ {
        z=z-(z*z-f)/(2*z)
    }
    return z, nil
}
 
func main() {
    fmt.Println(Sqrt(2))
    fmt.Println(Sqrt(-2))
}