1.2.md

Hello World Anatomy

any_name.go

package main

import "fmt"

func main() {
        fmt.Println("gophers")
}

Create this file anywhere, and run go run any_name.go

Let's break this file down:

any_name.go

• Filenames are generally snake_case.
• Filenames do not matter to the go compiler.

package main

• Every file in go belongs to a package which is stated in the first line of the file.
• main tells the Go compiler that the package should compile as an executable program instead of a shared library.

import "fmt"

• "fmt" is a package in the stdlib.
• Package names are lowercase, and have no underscores.
• Packages help group data and logic together.

func main() {

• Functions are declared with the func keyword.
• The main function is the entrypoint into the executable.

fmt.Println("gophers")

• Println is a function in the fmt package.
• Println is capitalized, making it exported and a part of the package's public API.
• The Println function from the fmt package is being used to print "gophers".
• go uses tabs, not spaces (which means you'll get paid less).

}

• This is the end of the main function.
• When main exits, the program will stop.

Exercises

To compile this, run go build any_name.go

To run the executable, run ./any_name

To run without creating an executable, run go run any_name.go

Tips

Go has great documentation: Try go doc fmt and go doc fmt Println, or see it online.

Further Reading

go help build

go help run

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