Hello World in golang

In this blog, we will

Install Go (if you haven't already)
Say Hello to the World
Use Go commands to run our code
Learn about packages and imports in Go
Learn about exported names

Install Go

Verify that you've installed Go by opening a command prompt and typing the following command:

go version

Confirm that the command prints the installed version of Go. For me, it's go1.22.1

go version go1.22.1 darwin/amd64

Hello World

Create hello a directory for Go source code

mkdir hello
cd hello

Enable dependency tracking for your code

When you write code and need to use packages from other sources, like libraries, you keep track of these connections using a file called go.mod. This file stays with your code and helps manage which packages your code relies on.

To set up this dependency tracking, you create a go.mod file by running the command go mod init followed by the name you want to give to your code's module. This name is often based on where your code is stored, like a repository location such as github.com/mymodule. If you plan to share your code with others, this name needs to be a place where Go Tools can find and download your code.

We will use example/hello

$ go mod init example/hello
go: creating new go.mod: module example/hello

Create a file, hello.go in which to write your code
Paste the following code into your hello.go file and save the file

package main

import "fmt"

func main() {
    fmt.Println("Hello, World!")
}

Package: a package is a way to group functions, and it's made up of all the files in the same directory

fmt package: This package is one of the standard library packages you got when you installed Go. which contains functions for formatting text, including printing to the console.

main function: A main function to print a message to the console. A nmain function executes by default when you run the main package.

Run the code to say Hello to the world

% go run .
Hello, World!

Congratulations! We have successfully said hello to the world.

Packages & Imports

Every Go program is made up of packages. Programs start running in package main.

package main

import (
    "fmt"
    "math/rand"
)

func main() {
    fmt.Println("My favorite number is", rand.Intn(10))
}

This program uses packages with import paths "fmt" and "math/rand".

By convention, the package name is the same as the last element of the import path. For instance, the "math/rand" package comprises files that begin with the statement package rand.

This code groups the imports into a parenthesized, "factored" import statement.

You can also write multiple import statements, like:

import "fmt"
import "math/rand"

But it is good style to use the factored import statement.

Exported names

In Go, a name is exported if it begins with a capital letter. For example, Pi, is exported from the math package.

When importing a package, you can refer only to its exported names. Any "unexported" names are not accessible from outside the package.

package main

import (
    "fmt"
    "math"
)

func main() {
    fmt.Println(math.pi)
}

There is an error in the above code. To fix the error, rename the math.pi to math.Pi .

See you soon!

Thanks for joining our journey to learn Go (Golang)! In our next blog, we'll dive deeper into Go programming essentials. Stay tuned for more exciting learning adventures! Don't forget to subscribe to our newsletter for updates.

Operations Guy