Book Image

The Go Workshop

By : Delio D'Anna, Andrew Hayes, Sam Hennessy, Jeremy Leasor, Gobin Sougrakpam, Dániel Szabó
5 (2)
Book Image

The Go Workshop

5 (2)
By: Delio D'Anna, Andrew Hayes, Sam Hennessy, Jeremy Leasor, Gobin Sougrakpam, Dániel Szabó

Overview of this book

The Go Workshop will take the pain out of learning the Go programming language (also known as Golang). It is designed to teach you to be productive in building real-world software. Presented in an engaging, hands-on way, this book focuses on the features of Go that are used by professionals in their everyday work. Each concept is broken down, clearly explained, and followed up with activities to test your knowledge and build your practical skills. Your first steps will involve mastering Go syntax, working with variables and operators, and using core and complex types to hold data. Moving ahead, you will build your understanding of programming logic and implement Go algorithms to construct useful functions. As you progress, you'll discover how to handle errors, debug code to troubleshoot your applications, and implement polymorphism using interfaces. The later chapters will then teach you how to manage files, connect to a database, work with HTTP servers and REST APIs, and make use of concurrent programming. Throughout this Workshop, you'll work on a series of mini projects, including a shopping cart, a loan calculator, a working hours tracker, a web page counter, a code checker, and a user authentication system. By the end of this book, you'll have the knowledge and confidence to tackle your own ambitious projects with Go.
Table of Contents (21 chapters)
Free Chapter
1
1. Variables and Operators
2
2. Logic and Loops

The nil Value

nil is not a type but a special value in Go. It represents an empty value of no type. When working with pointers, maps, and interfaces (we'll cover these in the next chapter), you need to be sure they are not nil. If you try to interact with a nil value, your code will crash.

If you can't be sure whether a value is nil or not, you can check it like this:

package main
import "fmt"
func main() {
  var message *string
  if message == nil {
    fmt.Println("error, unexpected nil value")
    return
  }
  fmt.Println(&message)
}

Running the preceding code shows the following output:

error, unexpected nil value

Activity 3.01: Sales Tax Calculator

In this activity, we create a shopping cart application, where sales tax must be added to calculate the total:

  1. Create a calculator that calculates the sales tax for a single item.
  2. The calculator...