Examples of Defining and Using Structs in Go

Introduction to Structs in Go

Structs in Go are a fundamental way to group related data into a single entity. They allow us to create complex types that represent real-world entities, making our code more organized and easier to manage. In this article, we’ll explore three diverse examples of defining and using structs in Go, showcasing their practical applications.

Example 1: Defining a Simple Struct for a Book

Use Case

We often need to represent books in applications, encompassing various attributes like title, author, and publication year. This example demonstrates how to define a struct for a book and use it to print book details.

package main

import (
    "fmt"
)

type Book struct {
    Title  string
    Author string
    Year   int
}

func main() {
    myBook := Book{
        Title:  "1984",
        Author: "George Orwell",
        Year:   1949,
    }

    fmt.Printf("Title: %s\nAuthor: %s\nYear: %d\n", myBook.Title, myBook.Author, myBook.Year)
}

Notes

• This struct model can be expanded with additional fields, such as Genre or ISBN, to provide more information about the book.
• You can also define methods on the struct for more functionality, such as displaying formatted information.

Example 2: Using Nested Structs for a Library System

Use Case

In a library management system, we might have a struct for a Library that contains multiple Books. This example illustrates how to define nested structs and iterate through a collection of books in a library.

package main

import (
    "fmt"
)

type Book struct {
    Title  string
    Author string
    Year   int
}

type Library struct {
    Name  string
    Books []Book
}

func main() {
    library := Library{
        Name: "City Library",
        Books: []Book{
            {Title: "1984", Author: "George Orwell", Year: 1949},
            {Title: "Brave New World", Author: "Aldous Huxley", Year: 1932},
        },
    }

    fmt.Printf("Library: %s\nBooks:\n", library.Name)
    for _, book := range library.Books {
        fmt.Printf("- %s by %s (%d)\n", book.Title, book.Author, book.Year)
    }
}

Notes

• The Books field in the Library struct is a slice of Book, allowing for dynamic lists of books.
• You can enhance this example by adding methods to the Library struct that perform operations like adding or removing books.

Example 3: Structs with Methods for a Student Management System

Use Case

In an educational application, we may want to manage student records. This example demonstrates how to define a struct for a Student, including methods to calculate their average grade.

package main

import (
    "fmt"
)

type Student struct {
    Name    string
    Grades  []float64
}

func (s Student) AverageGrade() float64 {
    total := 0.0
    for _, grade := range s.Grades {
        total += grade
    }
    return total / float64(len(s.Grades))
}

func main() {
    student := Student{
        Name:   "Alice",
        Grades: []float64{88.5, 92.0, 79.5},
    }

    fmt.Printf("Student: %s\nAverage Grade: %.2f\n", student.Name, student.AverageGrade())
}

Notes

• This struct includes a method AverageGrade, showcasing how you can encapsulate behavior related to the struct data.
• You could further extend this model by adding methods for other operations, such as adding grades or displaying student details.