Package basics

Context

Every Go file belongs to a package. A package is a collection of Go files in the same directory that are compiled together. The main package defines an executable program. Other packages are reusable libraries.

Example

Create two files in the same directory: main.go and math.go with package mymath.

Code example

// math.go
package mymath

func Add(a, b int) int {
    return a + b
}

// main.go
package main

import (
    "fmt"
    "mymath"
)

func main() {
    fmt.Println(mymath.Add(3, 4))
}

Output

7

Useful links

• Go spec: Packages
• How to write Go code