Understanding Structs in Golang

In Golang, a struct is a composite data type that groups together variables (called fields) under a single name.

Structs are used to create custom data types that can represent real-world entities or complex data structures.

Each field in a struct has a name and a type, and the fields can be of any valid Go type, including other structs.

Define a Struct

To define a struct in Golang, use the type keyword followed by the struct name and the list of fields enclosed in curly braces {}.

type User struct {
    Name    string
    Age     int
    Address string
}

In this example:

Create an Instance of a Struct

To create an instance of a struct, use the var keyword followed by the struct name and the field values enclosed in curly braces {}.

var user1 User
user1 = User{
    Name:    "Alice",
    Age:     30,
    Address: "123 Main St",
}

Here, user1 is an instance of the User struct with the specified field values.

Accessing Struct Fields

To access the fields of a struct, use the dot . operator followed by the field name.

fmt.Println(user1.Name)    // Output: Alice
fmt.Println(user1.Age)     // Output: 30
fmt.Println(user1.Address) // Output: 123 Main St

This will print the values of the fields Name, Age, and Address of the user1 struct instance.

Nested Structs

Structs can contain other structs as fields. This is useful for modeling more complex data structures.

type Address struct {
    City  string
    State string
}

type Person struct {
    Name    string
    Age     int
    Address Address
}

p := Person{
    Name: "Alice",
    Age:  30,
    Address: Address{
        City:  "New York",
        State: "NY",
    },
}
fmt.Println(p.Address.City)  // Output: New York

In this example, the Person struct contains an Address struct as a field. The Address struct has two fields: City and State.

Anonymous Structs

An anonymous struct is a struct without a name. It is defined and instantiated in a single line.

person := struct {
    Name string
    Age  int
}{
    Name: "Bob",
    Age:  25,
}

In this example, we define an anonymous struct with fields Name and Age and create an instance of it with the specified field values.

Summary

Structs are a fundamental concept in Golang that allows you to define custom data types by grouping together variables under a single name. They are used to represent real-world entities or complex data structures in a concise and readable way.

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