How do structs work in Go and how do you attach methods to them?

type Person struct {
    FirstName string
    LastName  string
    Age       int
    email     string   // unexported
}

// Creating struct instances
p1 := Person{FirstName: "Alice", LastName: "Smith", Age: 30}
p2 := &Person{FirstName: "Bob", Age: 25}  // pointer to struct

// Value receiver — works on a copy; cannot modify the original
func (p Person) FullName() string {
    return p.FirstName + " " + p.LastName
}

// Pointer receiver — modifies the original struct
func (p *Person) HaveBirthday() {
    p.Age++
}

fmt.Println(p1.FullName())   // Alice Smith
p1.HaveBirthday()            // Go auto-takes address: (&p1).HaveBirthday()
fmt.Println(p1.Age)          // 31

// Anonymous struct — useful for one-off data grouping
point := struct{ X, Y int }{X: 3, Y: 7}

// Struct embedding — promotes fields and methods (composition)
type Employee struct {
    Person               // embedded — promotes Name, HaveBirthday, etc.
    Company string
    Salary  float64
}
e := Employee{Person: Person{FirstName: "Carol", Age: 28}, Company: "Acme"}
fmt.Println(e.FullName())    // Carol  — promoted method