determines if a string is a valid IPv4 address in golang, but the correct way to do this is to use net.ParseIP() and check for err

is_ipv4.go

package main

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

func is_ipv4(host string) bool {
        parts := strings.Split(host, ".")

        if len(parts) != 4 {
                return false
        }

        for _, x := range parts {
                i, err := strconv.Atoi(x)
                if err != nil { // Check for the error first
                        return false
                }
                if i < 0 || i > 255 {
                        return false
                }
        }
        return true
}

func main() {
        addresses := []string{"192.168.1.1", "10.addr.3.4", "1.1.1", "1.r.4.5.3"}

        for _, address := range addresses {

                if is_ipv4(address) {
                        fmt.Printf("%s: This is a valid IPv4 address\n", address)
                        continue
                }
                fmt.Printf("%s: This is NOT a valid IPv4 address\n", address)
        }
}

should be len(parts) != 4, "1.1.1.1.1.1" for example is passed by this func

ok let me think about it, not sure I understand off the top of my head. And I need to properly format this and add a few more test cases in addresses []string eg "1.1.1", "1.1.1.1.1.1", "1.t.1"

ok figured out what line. fixed and added output of the tested addresses and a few extra test cases

Also removed else to be more idiomatic