Nested Structure in Golang

A structure or struct in Golang is a user-defined type that allows us to create a group of elements of different types into a single unit. Any real-world entity that has some set of properties or fields can be represented as a struct.

How to use nested structures in Golang

Go language allows nested structures. A structure that is a field of another structure is called a Nested Structure. In other words, a structure inside another structure is called a Nested Structure. Syntax:

type struct_name_1 struct{
  // Các trường
} 
type struct_name_2 struct{
  variable_name  struct_name_1

}

Consider the following example to understand nested structure in Golang:

Example 1:

// Chương trình Go minh hoạc
// cấu trúc lồng nhau
package main

import "fmt"

// Tạo cấu trúc
type Author struct {
	name string
	branch string
	year int
}

// Tạo cấu trúc lòng nhau
type HR struct {

	// cấu trúc là một trường
	details Author
}

func main() {

	// Khởi tạo các trường
	// của cấu trúc
	result := HR{
	
		details: Author{"Sona", "ECE", 2013},
	}

	// Hiện giá trị
	fmt.Println("\nDetails of Author")
	fmt.Println(result)
}

Result:

Details of Author
{{Sona ECE 2013}}

Example 2:

// Chương trình Golang minh họa
// cấu trúc lồng nhau
package main

import "fmt"

// Tạo cấu trúc
type Student struct {
	name string
	branch string
	year int
}

// Tạo cấu trúc lồng nhau
type Teacher struct {
	name string
	subject string
	exp	 int
	details Student
}

func main() {

	// Khởi tạo các trường
	// của cấu trúc
	result := Teacher{
		name: "Suman",
		subject: "Java",
		exp:	 5,
		details: Student{"Bongo", "CSE", 2},
	}

	// Hiện giá trị
	fmt.Println("Details of the Teacher")
	fmt.Println("Teacher's name: ", result.name)
	fmt.Println("Subject: ", result.subject)
	fmt.Println("Experience: ", result.exp)

	fmt.Println("\nDetails of Student")
	fmt.Println("Student's name: ", result.details.name)
	fmt.Println("Student's branch name: ", result.details.branch)
	fmt.Println("Year: ", result.details.year)
}

Result:

Details of the Teacher
Teacher's name:  Suman
Subject:  Java
Experience:  5

Details of Student
Student's name:  Bongo
Student's branch name:  CSE
Year:  2

Example 3:

In Go, a structure can have fields that are themselves structures, called nested structures. Here is an example of a structure that has a nested structure:

package main

import (
	"fmt"
)

type Address struct {
	Street	 string
	City	 string
	State	 string
	PostalCode string
}

type Person struct {
	FirstName string
	LastName string
	Age	 int
	Address Address
}

func main() {
	p := Person{
		FirstName: "John",
		LastName: "Doe",
		Age:	 30,
		Address: Address{
			Street:	 "123 Main St",
			City:	 "Anytown",
			State:	 "CA",
			PostalCode: "12345",
		},
	}

	fmt.Println(p.FirstName, p.LastName)
	fmt.Println("Age:", p.Age)
	fmt.Println("Address:")
	fmt.Println("Street:", p.Address.Street)
	fmt.Println("City:", p.Address.City)
	fmt.Println("State:", p.Address.State)
	fmt.Println("Postal Code:", p.Address.PostalCode)
}

Result:

John Doe
Age: 30
Address:
Street: 123 Main St
City: Anytown
State: CA
Postal Code: 12345

Here, we define two struct types: Person and Address. Person has a nested struct field called Address. In the main function, we create a new instance of Person with an Address field. Then, we print the values ​​of various fields of the Person and Address structs using dot notation to access the nested fields.