mkock

func main() {
	expressLine := busservice.Bus{"Express Line"}
	expressLine.Passengers := make([]busservice.Passenger, 0)
	expressLine.Passengers = append(expressLine.Passengers, busservice.Passenger{SSN: "001"})
	expressLine.Passengers = append(expressLine.Passengers, busservice.Passenger{SSN: "002"})

	// Get a manifest!
	ssns := make([]string, 0)
	for _, p := range expressLine.Passengers {
		ssns = append(ssns, p.SSN)

mkock

// Bus carries Passengers from A to B if they have a valid bus ticket.
type Bus struct {
	name string
	Passengers map[string]Passenger // Map of SSN to Passengers
}

mkock

// Bus carries Passengers from A to B if they have a valid bus ticket.
type Bus struct {
	name string
	passengers map[string]Passenger
}

// Add adds a single Passenger to the Bus. For brevity, we don't care too much about accidentally adding the same Passenger more than once.
func (b *Bus) Add(p Passenger) {
	if b.passengers == nil {
		b.passengers = make(map[string]Passenger)

mkock

func main() {
	expressLine := busservice.Bus{"Express Line"}
	expressLine.Add(busservice.Passenger{"001"})
	expressLine.Add(busservice.Passenger{"002"})
	
	// Get a manifest!
	ssns := make([]string, 0)
	expressLine.VisitPassengers(func(p busservice.Passenger) { ssns = append(ssns, p.SSN) })
	fmt.Printf("This bus carries %d passengers, here are their SSN's: %v\n", len(ssns), ssns)
}

mkock

// FindPassenger returns the Passenger that matches the given SSN, if found. Otherwise, an empty Passenger is returned.
func (b *Bus) FindPassenger(ssn string) Passenger {
	if p, ok := b.passengers[ssn]; ok {
		return p
	}
	return Passenger{} // A nobody.
}

mkock

// UpdatePassengers calls function visitor for each Passenger on the bus. Passengers are passed by reference and may be modified.
func (b *Bus) UpdatePassengers(visitor func(*Passenger)) {
	ps := make(map[string]Passenger, len(b.passengers))
	for ssn, p := range b.passengers {
		visitor(&p)
		ps[ssn] = p
	}
	b.passengers = ps
}

mkock

func main() {
	// Previous statements...

	// Assign seat numbers to passengers.
	var seatNumber uint8
	expressLine.UpdatePassengers(func(p *busservice.Passenger) {
		seatNumber++
		p.SeatNumber = seatNumber
	})

mkock

// Passengers represents a set of Passengers, using their SSN as key.
type Passengers map[string]Passenger

// NewPassengerSet returns an empty set of Passengers, ready to use.
func NewPassengerSet() Passengers {
	return make(map[string]Passenger)
}

// Add adds a Passenger to Passengers. The Passenger will be overwritten if exists.
func (p Passengers) Add(p Passenger) {

mkock

// Bus carries Passengers from A to B if they have a valid bus ticket.
type Bus struct {
	name string
	passengers Passengers
}

// NewBus returns a new Bus with an empty passenger set.
func NewBus(name string) Bus {
	b := Bus{}
	b.name = name

mkock

func main() {
	expressLine := busservice.NewBus()
	expressLine.Add(busservice.Passenger{SSN: "001"})
	expressLine.Add(busservice.Passenger{SSN: "002"})
	
	// Get a manifest!
	ssns := expressLine.Manifest()
	fmt.Printf("This bus carries %d passengers, here are their SSN's: %v\n", len(ssns), ssns)
}