Go Introduction

Go is a simple, fast and reliable programming language created at Google.

What is Go?

Go was designed at Google in 2007 and released publicly in 2009
It is a compiled language: your code is turned into a program file that runs directly
It is statically typed: every variable has a fixed type
It is known for being simple, with very few keywords

What is Go Used For?

Area	Example
Web servers and APIs	Backends for apps and websites
Cloud tools	Docker, Kubernetes, Terraform
Command-line tools	Small programs you run in the terminal
Networking	Proxies, chat servers, services that handle many users

How to Run Go

Go Playground: open go.dev/play in a browser, paste code, click Run. Nothing to install.
On your computer: download Go from go.dev/dl and install it. Check it with go version in the terminal.

To run a file on your computer, save it as main.go and type:

Example

bash

go run main.go

Your First Program

Example

package main

import "fmt"

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

Output

Hello, Workownix!

The example explained

Line	What it does
`package main`	Every Go file belongs to a package. `main` makes it a runnable program
`import "fmt"`	Loads the `fmt` package, used for printing (format)
`func main()`	The function where the program starts
`fmt.Println(...)`	Prints the text and a new line

Go is strict: if you import a package or create a variable and never use it, the program will not compile. This keeps code clean.

Printing Output

The fmt package has three main print functions:

Example

package main

import "fmt"

func main() {
	fmt.Print("Karachi ")
	fmt.Print("Lahore\n")
	fmt.Println("Price:", 250, "rupees")
	fmt.Printf("%s has %d students\n", "Class A", 30)
}

Output

Karachi Lahore
Price: 250 rupees
Class A has 30 students

Print prints exactly what you give it. \n is a new line.
Println adds spaces between values and a new line at the end.
Printf uses verbs like %s (string) and %d (whole number) to place values.

Comments

Example

// A single-line comment

/* A comment
   over several lines */

Go ignores comments. Use them to explain why your code does something.

Formatting Your Code

Go has an official style. The command go fmt formats your file automatically, and most editors run it when you save. Go code uses tabs for indentation, and the opening { must stay on the same line as func or if.

Exercise

Which line is needed to make a Go file a runnable program?

import "main"package mainfunc start()program main