Hello World in Go

Let's start with the traditional "Hello World" program. This simple program will help you understand the basic structure of a Go application.

Your First Go Program#

package main
 
import string">"fmt"
 
func main() {
    fmt.Println(string">"Hello World")
}
 

Let's break down this program:

• package main: Every Go file starts with a package declaration. The main package is special - it defines an executable program rather than a library.
• import "fmt": This imports the format package from the standard library, which provides formatting functions.
• func main(): The entry point of the program. Execution begins in the main function.
• fmt.Println("Hello World"): This prints the text "Hello World" to the console.

Running Your First Program#

To run this program, save it as hello.go and execute the following command:

go run hello.go
 

You should see Hello World printed to your console.

Building an Executable#

You can also compile your program into a standalone executable:

go build hello.go
 

This will create an executable file named hello (or hello.exe on Windows). You can run this executable directly:

./hello
 

Understanding Go Program Structure#

Every Go program follows a similar structure:

1. Package Declaration: All Go files begin with package <name>. Executable programs use package main.
2. Import Statements: Import other packages that your code needs.
3. Functions and Variables: Declare functions and variables. The main() function is required for executable programs.
4. Code Comments: Add documentation to your code using // for single-line comments or /* */ for multi-line comments.

Exercise#

Try modifying the "Hello World" program to:

1. Print your name instead of "Hello World"
2. Print multiple lines using multiple fmt.Println() calls
3. Add comments to explain what the program does

In the next module, we'll explore Go's variables and data types.