Struct in Go

In this tutorial, we will learn about structs in Go. Struct is short for Structures. We will cover the basics of defining and using structs, including how to create, access, and modify struct fields.

Understanding Structs in Go

A struct in Go is a composite data type that groups together variables under a single name. These variables, known as fields, can have different data types.

Defining a Struct

Structs in Go are defined using the struct keyword, followed by the field names and their types.

type Person struct {
    Name string
    Age  int
}

Creating an Instance of a Struct

You can create an instance of a struct by using the struct type followed by the field values in curly braces.

p := Person{Name: "Alice", Age: 25}

Accessing Struct Fields

Struct fields can be accessed using the dot operator.

fmt.Println(p.Name)
fmt.Println(p.Age)

Modifying Struct Fields

Struct fields can be modified by assigning new values to them.

p.Age = 26

Example 1: Defining and Creating a Struct

We can define and create an instance of a struct in Go.

For example,

  1. Define a struct named Person with fields Name and Age.
  2. Create an instance of the Person struct with initial values.
  3. Print the struct to the console.

Go Program

package main
import "fmt"
type Person struct {
    Name string
    Age  int
}
func main() {
    p := Person{Name: "Alice", Age: 25}
    fmt.Println(p)
}

Output

{Alice 25}

Example 2: Accessing Struct Fields

We can access fields of a struct in Go using the dot operator.

For example,

  1. Create an instance of the Person struct with initial values.
  2. Access and print the fields Name and Age to the console.

Go Program

package main
import "fmt"
type Person struct {
    Name string
    Age  int
}
func main() {
    p := Person{Name: "Alice", Age: 25}
    fmt.Println(p.Name)
    fmt.Println(p.Age)
}

Output

Alice
25

Example 3: Modifying Struct Fields

We can modify fields of a struct in Go by assigning new values to them.

For example,

  1. Create an instance of the Person struct with initial values.
  2. Modify the Age field of the struct.
  3. Print the modified struct to the console.

Go Program

package main
import "fmt"
type Person struct {
    Name string
    Age  int
}
func main() {
    p := Person{Name: "Alice", Age: 25}
    p.Age = 26
    fmt.Println(p)
}

Output

{Alice 26}

Example 4: Nested Structs

We can define a struct within another struct in Go.

For example,

  1. Define a struct named Address with fields City and State.
  2. Define a struct named Person with fields Name, Age, and Address.
  3. Create an instance of the Person struct with nested Address struct and print it to the console.

Go Program

package main
import "fmt"
type Address struct {
    City  string
    State string
}
type Person struct {
    Name    string
    Age     int
    Address Address
}
func main() {
    p := Person{
        Name: "Alice",
        Age:  25,
        Address: Address{
            City:  "New York",
            State: "NY",
        },
    }
    fmt.Println(p)
}

Output

{Alice 25 {New York NY}}