Go program structure

Introduction

A Go program needs a clear structure to run correctly. This structure tells the computer where to start and how to organize the code.

When writing any Go program, even a simple one.

When creating multiple files that work together in a Go project.

When you want to organize your code into packages for reuse.

When you want to run a Go program from the command line.

When you want to understand how Go programs start and run.

Syntax

Go

package main

import "fmt"

func main() {
    // program starts here
    fmt.Println("Hello, world!")
}

The package main line tells Go this is an executable program.

The main function is where the program starts running.

Examples

This is a simple Go program that prints a message.

Go

package main

import "fmt"

func main() {
    fmt.Println("Welcome to Go!")
}

This program imports two packages and prints the current time.

Go

package main

import (
    "fmt"
    "time"
)

func main() {
    fmt.Println("Current time:", time.Now())
}

Sample Program

This program shows the basic structure: package, import, and main function. It prints a message when run.

Go

package main

import "fmt"

func main() {
    fmt.Println("This is the start of a Go program.")
}

Important Notes

Every Go executable program must have package main and a main function.

Imports bring in code from other packages to use in your program.

The main function cannot take arguments or return values.

Summary

Go programs start with package main and a main function.

The main function is the entry point where the program runs.

Imports let you use other code libraries inside your program.