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.
Void identifier in Golang
_(underscore) in Golang is called Blank Identifier . Identifier is a user-defined name of program elements used for identification purposes.
Golang has a special feature of defining and using unused variables using Blank Identifier. Unused variables are those variables that are defined by the user during the program but he never uses them. These variables make the program almost unreadable. As you know, Golang is a more concise and readable programming language so it does not allow the programmer to define an unused variable. If you do so, the compiler will give you an error.
The real use of Blank Identifier comes when a function returns multiple values, but we only need a few values and need to get rid of the extra ones. It basically tells the compiler that this variable is not needed and ignores it without any error. It hides the values of the variable and makes the program readable. So whenever you assign a value to Blank Identifier, it will not be used.
Example 1: In the program below, the function mul_div returns two values and we store both values in mul and div identifiers . But in the entire program, we are using only one variable i.e. mul . So, the compiler will throw an error that div is declared and not used.
// Chương trình Go hiện trình biên dịch
// báo lỗi nếu một biến
// được khai báo nhưng không được sử dụng
package main
import "fmt"
// Hàm chính
func main() {
// gọi hàm này
// hàm trả về hai giá trị được gán
// cho định danh mul và div
mul, div := mul_div(105, 7)
// chỉ dùng biến mul
// trình biên dịch sẽ báo lỗi
fmt.Println("105 x 7 = ", mul)
}
// hàm trả về hai
// giá trị của kiểu integer
func mul_div(n1 int, n2 int) (int, int) {
// trả về các giá trị này
return n1 * n2, n1 / n2
}
Result:
./prog.go:15:7: div được khai báo nhưng không được dùngExample 2: Use the Blank identifier to fix the above program. Instead of the div identifier, just use _ (underscore) . It allows the compiler to ignore the declaration error and not use it for that particular variable.
// Chương trình Go dùng định danh trống
package main
import "fmt"
// Hàm chính
func main() {
// gọi hàm này
// hàm trả về hai giá trị
// được gán cho định danh mul và trống
mul, _ := mul_div(105, 7)
// chỉ dùng biến mul
fmt.Println("105 x 7 = ", mul)
}
// hàm trả về hai giá trị
// của kiểu integer
func mul_div(n1 int, n2 int) (int, int) {
// trả về giá trị này
return n1 * n2, n1 / n2
}
Result:
105 x 7 = 735Important points to remember:
- You can use multiple blank identifiers in the same program. So you can say that a Golang program can have multiple variables using the same identifier name blank.
- There are many cases where a value is required just to complete the syntax even though the values are known to not be used anywhere in the program. Like a function that returns multiple values. Most of such cases use the blank identifier.
- You can use any value of any type with Blank Identifier.
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.
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.
Methods with the same name in Golang
Golang allows creating two or more methods with the same name in the same package, but the receivers of these methods must be of different types.
Functions in Go
In Go, functions are blocks of code that perform specific tasks, which can be reused throughout the program to save memory, improve readability, and save time.
Variable Scope in Go
The scope of a variable in Golang determines which part of the program the variable is accessible to. In Go, all identifiers have a lexical scope that is determined at compile time.
Control Statements in Golang (if, if-else, Nested-if)
What conditional statements does Golang have? How to use conditional statements in Go programming? Let's find out together!
Short variable declaration operator in Go
The short variable declaration operator (:=) in Golang is used to create variables with a proper name and initial value. Here is what you need to know about the short variable declaration operator in Golang.
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