package main

import "fmt"

// A struct is a collection of fields. It's useful for grouping data together to form records.
type person struct {
	name string
	age  int
}

// A struct literal is a list of field values enclosed in braces. You can specify field names or just provide values in order.
// Instead of constructors, Go often uses factory functions that return a pointer to a struct.
// This allows for more flexible initialization and can encapsulate any setup logic.
func newPerson(name string) *person {

	p := person{name: name}
	p.age = 42
	return &p
}

func main() {

	// Here we create a new person struct using a struct literal. We specify the field values in order without field names.
	fmt.Println(person{"Bob", 20})

	// We can also specify field names in the struct literal. This way, the order of fields does not matter.
	fmt.Println(person{name: "Alice", age: 30})

	// Omitted fields will be set to their zero value. For example, the age field will be set to 0.
	fmt.Println(person{name: "Fred"})

	// You can also create a struct using the & operator to get a pointer to the struct. This is often more efficient when passing structs around.
	fmt.Println(&person{name: "Ann", age: 40})

	// Using a factory function to create a new person struct. This allows us to encapsulate any initialization logic and return a pointer to the struct.
	fmt.Println(newPerson("Jon"))

	s := person{name: "Sean", age: 50}
	// Struct fields are accessed using a dot.
	fmt.Println(s.name)

	// You can also access fields through a struct pointer.
	// The language automatically dereferences the pointer to access the field.
	sp := &s
	fmt.Println(sp.age)

	// Struct fields can be modified through a struct pointer as well. The following statement
	// also changes the value of s.age because sp and s point to the same struct in memory.
	sp.age = 51
	fmt.Println(sp.age)

	// Anonymous struct is a struct without a name. It's useful for grouping data together without having to define a new type.
	dog := struct {
		name   string
		isGood bool
	}{
		"Rex",
		true,
	}
	fmt.Println(dog)
}