Hello World

In the Go tutorial, you get started with Go in the typical manner: printing“Hello World” (Ken Thompson and Dennis Ritchie started this when they presentedthe C language in the 1970s). That’s a great way to start, so here it is, “HelloWorld” in Go.

package main 1
import "fmt" 2 // Implements formatted I/O.
/* Print something */ 3
func main() {         4
    fmt.Printf("Hello, world.") 5
}

Lets look at the program line by line. This first line is just required 1. AllGo files start with package <something>, and package main is required fora standalone executable.

import "fmt" says we need fmt in addition to main 2. A package otherthan main is commonly called a library, a familiar concept in many programminglanguages (see ). The line ends with a comment that begins with //.

Next we another comment, but this one is enclosed in / / 3. When your Goprogram is executed, the first function called will be main.main(), whichmimics the behavior from C. Here we declare that function 4.

Finally we call a function from the package fmt to print a string to thescreen. The string is enclosed with " and may contain non-ASCII characters5.