ex9.go

package contact

import (
	"strings"
	"fmt"
)

type friends struct {
	data []string
}

type person struct {
	name    string
	friends *friends
}

func NewFriends() *friends {
	return &friends{
		data: []string{},
	}
}

func (f *friends) Add(name string) {
	f.data = append(f.data, name)
}

func (f *friends) Remove(name string) {
	new := []string{}
	for _, friend := range f.data {
		if friend != name {
			new = append(new, friend)
		}
	}
	f.data = new
}

func (f *friends) String() string {
	return strings.Join(f.data, " ")
}

func NewPerson(name string) *person {
	return &person{
		name:    name,
		friends: NewFriends(),
	}
}

func (p *person) AddFriend(name string) {
	p.friends.Add(name)
}

func (p *person) RemoveFriend(name string) {
	p.friends.Remove(name)
}

func (p *person) GetFriends() *friends {
	return p.friends
}

func (p *person) String() string {
	return fmt.Sprintf("%s [%v]", p.name, p.friends)
}