contacts_struct.go

package main

import "fmt"

type Contact struct {
	Name  string
	Phone string
	Age   int
}

type Contacts []Contact

type Findable interface {
	Find(name string) Contact
}

func (self *Contacts) AddContact(contact Contact) {
	oldSlice := self
	*self = append(*oldSlice, contact)
}

func (self Contacts) Find(name string) Contact {
	for _, contact := range self {
		if contact.Name == name {
			return contact
		}
	}
	return Contact{}
}

func FindContact(contacts interface{}, name string) {
	if v, ok := contacts.(Findable); ok {
		contact := v.Find(name)
		fmt.Printf("Found %+v\n", contact)
	} else {
		fmt.Println("Interface not implemented")
	}
}

func main() {
	// contact := Contact{}
	contacts := Contacts{}
	contacts.AddContact(Contact{Name: "John"})
	fmt.Printf("%+v", contacts)
	FindContact(contacts, "John")

	// contacts := []Contact{}
	// _ = contacts
}