Main and init functions in Golang

Go language has reserved two special purpose functions and those functions are main() and init() . Here are the things to know about using main() and init() functions in Golang .

Main and init functions in Golang

main() function

In Go, the main package is a special package used with executable programs and this package contains the main() function . The main() function is a special type of function and is the entry point for executable programs. It does not take any arguments and does not return anything. Go automatically calls the main() function, so there is no need to call the main() function directly and every executable program must contain a main package and a unique main() function.

For example:

// Chương trình Go minh họa
// khái niệm của hàm main() 

// Khai báo gói chính
package main

// Nhập các gói
import (
    "fmt"
    "sort"
    "strings"
    "time"
)

// Hàm chính
func main() {

    // Sắp xếp slice đưa ra
    s := []int{345, 78, 123, 10, 76, 2, 567, 5}
    sort.Ints(s)
    fmt.Println("Sorted slice: ", s)

    // Tìm chỉ mục
    fmt.Println("Index value: ", strings.Index("Quantrimang", "ks"))

    // Tìm thời gian
    fmt.Println("Time: ", time.Now().Unix())

}

Result:

Sorted slice:  [2 5 10 76 78 123 345 567]
Index value:  3
Time:  1257894000

init() function

The init() function is just like the main function, it does not take any arguments and does not return anything. It is present in every package and is called when the package is initialized. It is implicitly declared, so you cannot reference it from anywhere and you are allowed to create multiple init() functions in the same program and they are executed in the order they are created. You are allowed to create init() functions anywhere in the program and they are called in the order of the dictionary file name (Alphabetical order). You are allowed to put statements if there is an init() function, but always remember that the init() function is executed before the main() function call, so it is independent of the main() function. The main purpose of the init() function is to initialize global variables that cannot be initialized in the global context.

For example:

// Chương trình Go minh họa
// khái niệm của hàm init() 

// Khai báo gói chính
package main

// Nhập gói
import "fmt"

// Hàm init() có nhiều nhánh
func init() {
    fmt.Println("Welcome to init() function")
}

func init() {
    fmt.Println("Hello! init() function")
}

// Hàm chính
func main() {
    fmt.Println("Welcome to main() function")
}

Result:

Welcome to init() function
Hello! init() function
Welcome to main() function

Leave a Comment

How to use constants in Golang

How to use constants in Golang

What is a Constant or Const in Golang? Here's what you need to know about using constants in Go.

Volatile functions in Golang

Volatile functions in Golang

Variadic functions in Go allow you to pass a variable number of arguments to a function. Here's everything you need to know about variadic functions in Golang.

Named return parameters in Golang

Named return parameters in Golang

In Golang, named return parameters are often referred to as named parameters. Golang allows naming the return parameters or results of functions in the function signature or definition.

Keywords in Go

Keywords in Go

Keyword - Keywords are words in a language that are used for some internal processes or represent some predefined actions. Here is what you need to know about keywords in Golang.

Data types in Golang

Data types in Golang

Data types specify what type of data a valid Go variable can hold. In the Go language, types are divided into four categories as follows:

Function arguments in Golang

Function arguments in Golang

Go supports two main ways to pass arguments: Pass by Value and Pass by Reference. Go uses pass by value by default.

Function returning multiple values ​​in Golang

Function returning multiple values ​​in Golang

In Go language, you are allowed to return multiple values ​​from a function, using the return statement. In other words, in a function, a return statement can return multiple values.

Switch Statement in Go

Switch Statement in Go

Golang like most other programming languages ​​has switch statement. Here is how to use switch statement in Golang.

Cases to know when using selection statements in Golang

Cases to know when using selection statements in Golang

In this article, we will learn how to use default case to avoid deadlock. But first, we will learn what is deadlock case when using select command in Golang?

Anonymous structures and fields in Golang

Anonymous structures and fields in Golang

Anonymous structs in Golang are temporary structures with no names used for one-time purposes, while anonymous fields allow embedding of unnamed fields.

How to use Rune in Golang

How to use Rune in Golang

What is Rune in Golang? How to use Rune in Golang? This article will give you the answer.

How to use operators in Golang

How to use operators in Golang

Operators allow us to perform different types of operations on operands. In Go language, operators can be classified based on their different functions.

Void identifier in Golang

Void identifier in Golang

_(underscore) in Golang is called Blank Identifier. Identifier is a user-defined name of program elements used for identification purposes.

How to create basic program in Golang

How to create basic program in Golang

Hello, World! is the first basic program in any programming language. You can write this first program in Golang by following the steps below.

How to Install Go on Windows

How to Install Go on Windows

Golang can be easily installed on Windows. Here is a step-by-step guide to install Golang on Windows.

How to Fix Microsoft Teams Error K Security

How to Fix Microsoft Teams Error K Security

Struggling with Microsoft Teams "Error K" Security? Follow our step-by-step guide to fix it quickly—no tech expertise needed. Get back to seamless collaboration today!

How to Fix Microsoft Teams Update Error 0x80070002

How to Fix Microsoft Teams Update Error 0x80070002

Struggling with Microsoft Teams Update Error 0x80070002? Discover step-by-step fixes to resolve it quickly. Clear cache, repair files, and get back to seamless updates today!

Solving Microsoft Teams Web Error Browser Login

Solving Microsoft Teams Web Error Browser Login

Tired of Microsoft Teams "Web Error" blocking your browser login? Follow our step-by-step guide with proven fixes to resolve Teams web login issues fast and securely. Get back to work!

How to Fix Microsoft Teams Error O Offline

How to Fix Microsoft Teams Error O Offline

Stuck with Microsoft Teams "Error O" Offline? Discover proven, step-by-step fixes to get back online fast. Clear cache, restart, and more – no tech skills needed!

Where is Microsoft Teams in Outlook? Locating the Missing Icon

Where is Microsoft Teams in Outlook? Locating the Missing Icon

Frustrated by the missing Microsoft Teams icon in Outlook? Learn exactly where to find it, why it disappears, and proven steps to restore it for effortless meetings. Updated for the latest versions!

Solving Microsoft Teams Windows 10 Error Login Issues

Solving Microsoft Teams Windows 10 Error Login Issues

Struggling with Microsoft Teams "Windows 10 Error" login issues? Get instant fixes for cache clears, updates, and more. Step-by-step solutions to solve Microsoft Teams login error on Windows 10 fast and frustration-free.

Solving Microsoft Teams Website Error Tab Not Loading

Solving Microsoft Teams Website Error Tab Not Loading

Tired of the frustrating Microsoft Teams "Website Error" where tabs won’t load? Get step-by-step fixes to resolve it quickly and boost your productivity. Essential troubleshooting for seamless Teams experience.

How to Fix Microsoft Teams Web Error 503 Service Unavailable

How to Fix Microsoft Teams Web Error 503 Service Unavailable

Tired of the frustrating Microsoft Teams "Web Error" 503 Service Unavailable? Discover proven, step-by-step fixes for Teams 503 error on web. Get back online fast with our expert guide. Works on all browsers!

How to Fix Microsoft Teams Win 7 Error Compatibility

How to Fix Microsoft Teams Win 7 Error Compatibility

Struggling with Microsoft Teams "Win 7 Error" compatibility? Discover step-by-step fixes to restore seamless video calls and chats on unsupported Windows versions. Quick, reliable solutions inside!

Troubleshooting Microsoft Teams Breakout Rooms License Errors

Troubleshooting Microsoft Teams Breakout Rooms License Errors

Master troubleshooting Microsoft Teams Breakout Rooms license errors with this step-by-step guide. Quick fixes for common license issues, admin checks, and prevention tips to get your meetings running smoothly.

How to Fix Microsoft Teams Version History Error

How to Fix Microsoft Teams Version History Error

Struggling with Microsoft Teams "Version History" Error? Discover proven, step-by-step fixes to restore access instantly. Clear cache, update Teams, and more—no tech skills needed!

Solving Microsoft Teams Joining Error: Meeting ID Not Found

Solving Microsoft Teams Joining Error: Meeting ID Not Found

Tired of the frustrating Microsoft Teams Joining Error: Meeting ID Not Found? Get step-by-step fixes to rejoin meetings fast. Updated with the latest Teams patches for seamless collaboration. Solve it now!

Troubleshooting Microsoft Teams Video Error Green Screen

Troubleshooting Microsoft Teams Video Error Green Screen

Struggling with Microsoft Teams "Video Error" green screen? Discover proven, step-by-step troubleshooting fixes for seamless video calls. Quick solutions inside!

How to Fix Microsoft Teams How Teams Works Tutorial Error

How to Fix Microsoft Teams How Teams Works Tutorial Error

Struggling with the Microsoft Teams "How Teams Works" Tutorial Error? Discover proven, step-by-step fixes to resolve it quickly. Clear cache, update, and more for seamless onboarding. Works on latest versions!

How to Fix Microsoft Teams Error Today on Windows 10

How to Fix Microsoft Teams Error Today on Windows 10

Tired of the frustrating Microsoft Teams "Error Today" on Windows 10? Discover proven, step-by-step fixes to resolve it quickly and restore smooth teamwork. No tech skills needed!