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.
Defer Keyword in Golang
In Go, defer statements delay execution of a function or method or an anonymous method until the surrounding function returns. In other words, the arguments to the defer function or method are evaluated immediately, but they do not execute until the surrounding function returns. You can create a deferred method, function, or anonymous function using the defer keyword.
Syntax:
// Hàm
defer func func_name(parameter_list Type)return_type{
// Code
}
// Phương thức
defer func (receiver Type) method_name(parameter_list){
// Code
}
defer func (parameter_list)(return_type){
// code
}()Important Note:
- In Go language, multiple defer statements are allowed in the same program and they are executed in LIFO (Last-In, First-Out) order as shown in Example 2.
- In defer statements, the arguments are evaluated when the defer statement is executed, not when it is called.
- Defer statements are often used to ensure that files are closed when their need ends, or to close channels, or to catch problems in the program.
Now let's look at an example to understand better.
Example 1:
// Chương trình Go minh họa
// khái niệm của lệnh defer
package main
import "fmt"
// Các hàm
func mul(a1, a2 int) int {
res := a1 * a2
fmt.Println("Result: ", res)
return 0
}
func show() {
fmt.Println("Hello!, Quantrimang.com")
}
// Hàm chính
func main() {
// Gọi hàm mul()
// Tại đây hàm mul hoạt động
// như một hàm bình thường
mul(23, 45)
// Gọi hàm mul()
// Dùng từ khóa defer
// Hàm the mul()
// là hàm defer
defer mul(23, 56)
// Gọi hàm show()
show()
}
Result:
Result: 1035
Hello!, Quantrimang.com
Result: 1288Explanation: In the above example, we have two functions named mul() and show() . While the show() function is called normally in the main() function , the mul() function is called in two different ways:
- First, we call the mul function normally (without the defer keyword), i.e. mul(23, 45) and it executes when the function is called (Output: Result: 1035).
- Second, we call the mul() function as a defer function using the defer keyword, i.e. defer mul(23, 56) and it executes (Output: Result: 1288) when all the surrounding methods return.
Example 2:
// Minh họa chương trình Go
// dùng nhiều lệnh defer, để minh họa chính sách LIFO
package main
import "fmt"
// Các hàm
func add(a1, a2 int) int {
res := a1 + a2
fmt.Println("Result: ", res)
return 0
}
// Hàm chính
func main() {
fmt.Println("Start")
// Nhiều lệnh defer
// Triển khai theo thứ tự LIFO
defer fmt.Println("End")
defer add(34, 56)
defer add(10, 10)
}
Result:
Start
Result: 20
Result: 90
EndVolatile 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
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
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 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
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
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
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
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 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
What is Rune in Golang? How to use Rune in Golang? This article will give you the answer.
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
_(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
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
Golang can be easily installed on Windows. Here is a step-by-step guide to install Golang on Windows.
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