package main

import "fmt"

type IPAddr [4]byte

// TODO: Add a "String() string" method to IPAddr.
func (ip IPAddr) String() string {
    rs := ""

    for k, v := range ip {
        if k == 0 {
            rs += fmt.Sprintf("%v", v)
            continue
        }

        rs += fmt.Sprintf(".%v", v)
    }

    return rs
}

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

package main

import (
    "fmt"
    "net"
)

type IPAddr [4]byte

func (ip IPAddr) String() string {
    return net.IP(ip[:]).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: %vn", name, ip)
    }
}

loopback: 127.0.0.1
googleDNS: 8.8.8.8

package main

import (
    "fmt"
    "strconv"
)

type IPAddr [4]byte

func (ip IPAddr) String() string {
    s := make([]byte, 0, (1+3)*len(IPAddr{}))
    for i, b := range ip {
        if i > 0 {
            s = append(s, ',')
        }
        s = strconv.AppendInt(s, int64(b), 10)
    }
    return string(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: %vn", name, ip)
    }
}

loopback: 127,0,0,1
googleDNS: 8,8,8,8

package main

import (
    "fmt"
    "testing"
)

type IPAddr [4]byte

func (ip IPAddr) String() string {
    rs := ""
    for k, v := range ip {
        if k == 0 {
            rs += fmt.Sprintf("%v", v)
            continue
        }
        rs += fmt.Sprintf(".%v", v)
    }
    return rs
}

func BenchmarkString1(b *testing.B) {
    hosts := map[string]IPAddr{
        "loopback":  {127, 0, 0, 1},
        "googleDNS": {8, 8, 8, 8},
    }
    for N := 0; N < b.N; N++ {
        for name, ip := range hosts {
            fmt.Sprintf("%v: %vn", name, ip)
        }
    }
}

BenchmarkString1-8    841730   1412 ns/op   176 B/op   19 allocs/op
BenchmarkString2-8   1228399    931 ns/op   128 B/op    8 allocs/op
BenchmarkString3-8   1984806    574 ns/op   128 B/op    8 allocs/op
BenchmarkString4-8   1765022    626 ns/op   128 B/op    8 allocs/op

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