Your first program

Context

Every Go program is composed of packages. A package named main is special: it defines an executable program. The entry point is a function named main with no parameters and no return values.

Structure of a Go source file

package main                     // Package declaration

import "fmt"                     // Import statement (standard library)

func main() {                    // Entry point function
    fmt.Println("Hello, World")  // Statement
}

Explanation

package main – Declares that this file belongs to the main package.
import "fmt" – Imports the fmt package for formatted I/O.
func main() – The program starts here. No arguments, no returns.
fmt.Println – Prints a line to standard output.

Running the program

Save the code as main.go, then in a terminal:

go run main.go

Example

Create a file main.go with the content below.

Code example

package main

import "fmt"

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

Output

Hello, World