Golang Interview Questions and Answers
An open-source programming language developed by Google, Go is designed for building fast and reliable applications. It is a statically-typed language that has a similar syntax to C. This information has been asked quite a few times recently in Golang interview questions. Some of its main features include dynamic typing, rich library, a documentation engine called GoDoc that is used by the entire Go community, static code analysis, and built-in testing tools that are simple and efficient.
| Quick Facts About Go Programming | |
|---|---|
| What is the latest version of Go? | 1.14.4 released on 1st June 2020. |
| When did Go programming release? | 10th November 2009. |
| Who is the developer of Golang? | It is designed at Google and developed by Robert Griesemer, Rob Pike, and Ken Thompson. |
| What language does Golang use? | The former was written in C but now written in Go itself. |
Most Frequently Asked Golang Interview Questions
Generally, large programs are made of many multiple small subprograms. For example, a server handles multiple requests made via web browsers and serves HTML web pages in response. In this case, each request made is considered as a small program.
Golang makes it possible to run smaller components of each of these programs simultaneously through concurrency. It has extensive support for concurrency using goroutines and channels
Golang language interfaces are different from other languages. In Golang, type implements an interface through the implementation of its methods. There are no explicit declarations or no “implements” keyword.
package main
import "fmt"
type I interface {
M()
}
type T struct {
S string
}
// This method means type T implements the interface I,
// but we don't need to explicitly declare that it does so.
func (t T) M() {
fmt.Println(t.S)
}
func main() {
var i I = T{"hello"}
i.M()
}
package main
import "fmt"
func main() {
fmt.Println(functionByBestInterviewQuestion())
}
func functionByBestInterviewQuestion() []int {
a, b := 15, 10
b, a = a, b
return []int{a, b}
}
Golang's small syntax and concurrency model make it a without a doubt speedy programming language. Golang is compiled to machine code and its compilation system is very fast. Go additionally hyperlinks all the dependency libraries into a single binary file as a consequence putting off the dependency on servers.
To check if the array is empty follow these steps:
Check with the builtin len() function, for example, len(slice) <= 0. If the array is empty, skip the for a loop.
r := whatever()
if len(r) > 0 {
// do what you want
}
- Concise, simple to work and Scalable
- Built-in support for other applications
- Good speed across platforms like OS X, Linux, and Windows.
- Ability to cross-compile the application to run on different devices than the ones used for development
- Automatic management of memory
It is a directory hierarchy with three directories – src, pkg and bin - at its root that contain the Go code. The "src" directory includes source files, the "pkg" directory contains objects, and the "bin" directory contains commands.
Note: This information is usually asked in golang interview questions.
In Golang, a channel is a communication object which uses goroutines to communicate with each other. Technically, it is a data transfer pipe in which data can be transferred into or read from.
It is a function that runs concurrently with other functions. If you want to stop it, you will have to pass a signal channel to the goroutine, which will push a value into when you want the function to finish.
Quit : = make (chan bool)
go func ( ) {
for {
select {
case <- quit:
return
default
// do other stuff
}
}
}()
// Do stuff
// Quit goroutine
Quit <- true
Yes, Golang supports multithreading. Moreover, its design is based on multithreading.
Rvalue
- Shows on assignment operator's right side.
- Always assigned to lvalue.
Lvalue
- Shows on assignment operator's left side.
- Designated to a variable and not a constant.
The command line argument can be accessed using the os.Args variables.
For instance:
Package main
import (
“fmt”
“OS”
)
func main () {
fmt.Println(len(os.Args), os.Args)
}
In Golang, the Cgo lets all the Go packages call a C code. With a Go source file written on some special features, the cgo makes an output in Go and C files which can be then combined into a single Go package bundle.
Concurrency potential that two or extra calculations manifest inside the identical time frame, and there is usually some kind of dependency between them. Parallelism capacity that two or extra calculations show up simultaneously.
In Golang, a shadowed variable is one which is declared in an inner scope having the same name and type as a variable in the outer scope. Here, the outer variable is mentioned after the inner variable is declared.
It refers to a string constant which is obtained by concatenating an arrangement of characters. String literals are of two types - Raw string literals and Interpreted string literals.
The Go memory allocator preserves a significant portion of virtual memory for allocations, which is local to the specific Go process.
To test on Golang, follow these steps:
- Create a file and end it with _test.go.
- This file should contain the TestXxx functions as described.
- Now, put this file in the same package as the one which is being tested.
- This file will now be included in the “go test” command.
| GOPATH | GOROOT |
|---|---|
| This must be set in order to get, develop and install packages outside the standard Golang tree. | Must be set only when installing to a specific custom location. |
Here are some of the built-in supports:
- Container: container/list,container/heap
- Web Server: net/http
- Cryptography: Crypto/md5 ,crypto/sha1
- Compression: compress/ gzip
- Database: database/sql
Break statement: It terminates the “for” loop or switch statement and transfers execution following the “for” loop or switch.
Continue statement: It helps the loop to omit the remainder of its body and retest before repeating.
Goto statement: It transfers control to the statement
Every GO program is built of packages that are used to organize source code for readability and reusability. Packages make it easy to maintain applications. The abbreviation for a package is “fmt”.
It is used for loop to iterate over items of slice array, map or channel.
A particular type known as type switch is used to check variable type at runtime and switch.
When a pointer is assigned “nil”, it called a nil pointer. It is a constant with a “zero” value defined in standard libraries.
Godoc extracts package documentation from the source code that can be utilized on the command line or the web. An instance is golang.org/pkg/.
Actual parameters: Parameters that are sent to the function at the calling end.
Formal Parameters: Parameters that are at the receiving of the function definition.
A loop statement allows programmers to execute a statement multiple times. Here is a general type of loop statement used in the majority of programming languages:
Loop Control Statements: These statements change execution from the typical sequence. When an implementation leaves a scope, every programmed object gets diminished.
The Infinite Loop: A loop will turn into an infinite loop if its condition is never false. It is possible to create endless loops by keeping the conditional expression empty.
It is a strategy for creating software by separating the functionality of a program into a different independent and exchangeable modules that are clubbed together to achieve the final software.
This is an essential topic in GO interview questions and Answers.
Go Array allows programmers to define factors that can hold information of a similar kind yet not give any strategy for building size or for getting a sub-exhibit. Slice takes care of this limitation. It provides utility functions needed on Array and is a part of Go programming.
It is one of the data types that allow programmers to combine data items of different types. There are two types of structure - type and struct. Once you set up a structure, you can use it to declare variables.
It is a way to identify the behavior of objects. Developed with the help of “type” followed by the name and keyword, it is used to represent a pair by furnishing information stored in interface and pointer.
It is used to check values that are held by interface type variable. It is also used to convert various GO types.
func function_name( [parameter list] ) [return_types] {
// the body of the function
}
var x, y, z = 3, 4, "foo"
fmt.Printf("x is of type %Tn", x)
- Call by value
- Call by reference
A token is either a keyword, an identifier, a constant, a string literal, or a symbol in GO Programming used.
Advantages
- Concise, simple to work and Scalable
- Built-in support for other applications
- Good speed across platforms like OS X, Linux, and Windows.
- Ability to cross-compile the application to run on different devices than the ones used for development
- Automatic management of memory
Are you looking for Golang Interview Questions? As a developer, you would want to know the best possible Questions that you might be asked in your Job Interview.