A Tour of Go Exercise: Stringers

exercise-stringer.go

package main

import (
	"fmt"
	"strings"
	"strconv"
)

type IPAddr [4]byte

func (ip IPAddr) String() string {
	s := make([]string, len(ip))
	for i, val := range ip {
		s[i] = strconv.Itoa(int(val))
	}	
	return strings.Join(s, ".")
}

func main() {
	hosts := map[string]IPAddr{
		"loopback":  {127, 0, 0, 1},
		"googleDNS": {8, 8, 8, 8},
	}
	for name, ip := range hosts {
		fmt.Printf("%v: %v\n", name, ip)
	}
}

Mine lol

package main

import "fmt"

type IPAddr [4]byte

// TODO: Add a "String() string" method to IPAddr.
func (ip_add IPAddr) String() string {
	return fmt.Sprintf("%d.%d.%d.%d", ip_add[0],ip_add[1],ip_add[2],ip_add[3])
}

func main() {
	hosts := map[string]IPAddr{
		"loopback":  {127, 0, 0, 1},
		"googleDNS": {8, 8, 8, 8},
	}
	for name, ip := range hosts {
		fmt.Printf("%v: %v\n", name, ip)
	}
}

package main

import "fmt"

type IPAddr [4]byte

// TODO: Add a "String() string" method to IPAddr.

func (ip IPAddr) String() string {
	return fmt.Sprintf("%v.%v.%v.%v\n", ip[0],ip[1], ip[2], ip[3])
}

func main() {
	hosts := map[string]IPAddr{
		"loopback":  {127, 0, 0, 1},
		"googleDNS": {8, 8, 8, 8},
	}
	for name, ip := range hosts {
		fmt.Printf("%v: %v\n", name, ip)
	}
}

package main

import "fmt"

type IPAddr [4]byte

func (ip IPAddr) String() string {
	return fmt.Sprintf("%d.%d.%d.%d", ip[0], ip[1], ip[2], ip[3])
}

func main() {
	hosts := map[string]IPAddr{
		"loopback":  {127, 0, 0, 1},
		"googleDNS": {8, 8, 8, 8},
	}
	for _, ip := range hosts {
		fmt.Println(ip.String())
	}
}

Nice answer, I couldn't think of it

package main

import "fmt"

type IPAddr [4]byte

// TODO: Add a "String() string" method to IPAddr.
func (ip IPAddr) String() string {
	var ipFinal string = ""
	for i := range ip {
		if i < 3 {
			ipFinal = ipFinal + fmt.Sprintf("%d", ip[i]) + "."
		} else {
			ipFinal = ipFinal + fmt.Sprintf("%d", ip[i])
		}
	}
	return ipFinal
}

func main() {
	hosts := map[string]IPAddr{
		"loopback":  {127, 0, 0, 1},
		"googleDNS": {8, 8, 8, 8},
	}
	for name, ip := range hosts {
		fmt.Printf("%v: %v\n", name, ip)
	}
}

package main

import (
	"fmt"
	"strings"
	"strconv"
)

type IPAddr [4]byte

// TODO: Add a "String() string" method to IPAddr.
func (ip IPAddr) String() string {
	s := make([]string, len(ip))
	for i, val := range ip {
		s[i] = strconv.Itoa(int(val))
	}
	return strings.Join(s, ".")
}

func main() {
	hosts := map[string]IPAddr{
		"loopback":  {127, 0, 0, 1},
		"googleDNS": {8, 8, 8, 8},
	}
	for name, ip := range hosts {
		fmt.Printf("%v: %v\n", name, ip)
	}
}

I'm using append instead of concat string

package main

import (
	"fmt"
	"strings"
	"strconv"
)

type IPAddr [4]byte

func (ip IPAddr) String() string {
	s := make([]string, len(ip))
	
	for _, v := range ip {
		s = append(s, strconv.Itoa(int(v)))
	} 
	
	return strings.Join(s, ".")
}

func main() {
	hosts := map[string]IPAddr{
		"loopback":  {127, 0, 0, 1},
		"googleDNS": {8, 8, 8, 8},
	}
	for name, ip := range hosts {
		fmt.Printf("%v: %v\n", name, ip)
	}
}

I think it'd be better to declare the slice s like make([]string, 0, len(ip)). Otherwise, the output would be like "....127.0.0.1" as the append will add the digit from index 4.

I've tried to keep it simple and used the strings.Builder type to create the desired result

package main

import (
	"fmt"
	"strings"
)

type IPAddr [4]byte

func (ip IPAddr) String() string {
	var b strings.Builder
	for _, v := range ip {
		fmt.Fprintf(&b, "%d.", v)
	}
	return strings.Trim(b.String(), ".")
}

func main() {
	hosts := map[string]IPAddr{
		"loopback":   {127, 0, 0, 1},
		"googleDNS":  {8, 8, 8, 8},
	}
	for name, ip := range hosts {
		fmt.Printf("%v: %v\n", name, ip)
	}
}