Structs in Golang

A struct in Golang is a user-defined type that allows to combine different types of variables into single type.
In Golang, Structures does not support inheritance but supports composition.
We can define a struct using a keyword struct.
Syntax: type struct_name struct{}

Example:

 package main
 import "fmt"
 type User struct {
	name string
	age  int
 }
 func main() {
	// declare a struct variable
	var user1 User
	user1.name = "vicky"
	user1.age = 22
    
	// declaration and initialization of struct at a same to a struct variable
	user2 := User{"tejas", 23}
    
	// you can define a struct address to a varibale while initializing
	user3 := &User{"vinu", 23}
	fmt.Println("user 1 : "user1)
	fmt.Println("user 2 : "user2)
	fmt.Println("user 3 : "*user3)
 }

Output:

user 1 :  {vicky 22}
user 2 :  {tejas 23}
user 3 :  {vinu 23}

Anonymous Struct in Golang:

A anonymous struct is a struct with no name. It's useful when you want create a one time useable struct.

Example for Anonymous struct:

 package main
 import "fmt"
 func main() {

	// struct with no struct name
	user1 := struct {
		name string
		age  int
	}{"vicky", 22}

	// struct with no struct name and no field names
	user2 := struct {
		string
		int
	}{"tejas", 23}

	fmt.Println("user 1 : ", user1)
	fmt.Println("user 2 : ", user2)
 }

Output:

user 1 :  {vicky 22}
user 2 :  {tejas 23}

Important Note: if we use an Anonymous struct with no field names, same types of variables is not allowed

 package main
 import "fmt"
 func main() {
	// struct with no struct name and no field names
	s1 := struct {
		int
		int
	}{23, 23}
	fmt.Println(s1)
 }

Output:

./prog.go:9:3: int redeclared
	./prog.go:8:3: other declaration of int
./prog.go:10:8: too many values in struct literal of type struct{int}