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.
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() 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
What is a Constant or Const in Golang? Here's what you need to know about using constants in Go.
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.
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.
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 specify what type of data a valid Go variable can hold. In the Go language, types are divided into four categories as follows:
Go supports two main ways to pass arguments: Pass by Value and Pass by Reference. Go uses pass by value by default.
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.
Golang like most other programming languages has switch statement. Here is how to use switch statement 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 structs in Golang are temporary structures with no names used for one-time purposes, while anonymous fields allow embedding of unnamed fields.
What is Rune in Golang? How to use Rune in Golang? This article will give you the answer.
Operators allow us to perform different types of operations on operands. In Go language, operators can be classified based on their different functions.
_(underscore) in Golang is called Blank Identifier. Identifier is a user-defined name of program elements used for identification purposes.
Hello, World! is the first basic program in any programming language. You can write this first program in Golang by following the steps below.
Golang can be easily installed on Windows. Here is a step-by-step guide to install Golang on Windows.
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