Package scope rules in Go - Mini Project: Build & Apply

Package scope rules

📖 Scenario: You are creating a simple Go program to understand how variables and functions are accessible within a package.

🎯 Goal: Build a Go program that shows how package-level variables and functions can be accessed inside the same package.

📋 What You'll Learn

Create a package-level variable

Create a package-level function

Access the variable and function inside the main function

Print the results to the console

💡 Why This Matters

🌍 Real World

Understanding package scope is essential for organizing Go programs into reusable and maintainable parts.

💼 Career

Go developers frequently use package-level variables and functions to share data and logic within packages, making this knowledge critical for writing clean and effective Go code.

1

Create a package-level variable

Create a package-level variable called message of type string and set it to "Hello from package scope!".

Go

package main

// Create a package-level variable called message

func main() {

}

Hint

Package-level variables are declared outside of any function but inside the package.

2

Create a package-level function

Create a package-level function called getMessage that returns a string and returns the message variable.

Go

package main

var message string = "Hello from package scope!"

// Create a package-level function getMessage that returns message

func main() {

}

Hint

Functions declared outside main() are package-level and can be used anywhere in the package.

3

Access the variable and function inside main

Inside the main function, create a variable called msgFromVar and assign it the value of the package-level variable message. Then create a variable called msgFromFunc and assign it the result of calling the getMessage() function.

Go

package main

var message string = "Hello from package scope!"

func getMessage() string {
    return message
}

func main() {
    // Assign message to msgFromVar
    // Assign getMessage() result to msgFromFunc
}

Hint

You can use package-level variables and functions directly inside main().

4

Print the results

Add import "fmt" at the top. Inside the main function, print msgFromVar and msgFromFunc each on a new line using fmt.Println.

Go

package main

import "fmt"

var message string = "Hello from package scope!"

func getMessage() string {
    return message
}

func main() {
    msgFromVar := message
    msgFromFunc := getMessage()
    // Print msgFromVar
    // Print msgFromFunc
}

Hint

Use fmt.Println to print each message on its own line.