Top 20 Golang Interview Questions with Answers

Hello guys, if you are preparing for Golang Developer Job interview and looking for frequently asked Golang Interview questions then you have come to the right place. Golang is one of the modern and in-demand programming language from Google and more and more companies have started using Golang for their flagship project like ByteDance is using Golang for TikTok and their other projects. In the past, I have shared best Golang courses  as well as free Golang courses and in this article, I am going to share 20 common Golang Interview Questions with Answers. These questions covers essential Golang concepts which every Golang developer should be familiar with. 

If you have worked in Golang or used Golang in one of project then most likely you can answer these questions but if you struggle to answer them then you can always go back and join one of these Golang online courses and classes to learn and revise essential Golang concepts. 

20 Golang Interview Questions with Answers

Golang is not as hard as you think. Golang interview is also something easy that you can pass. Passing this kind of interview just needs you to know and understand the type of questions that will be asked during the interview. Once you know the questions, you should also strive to know the correct answers and everything will be easier. To help you achieve that, the top 20 Golang interview questions with answers have been listed below.

1. What is the Go programming language?
Answer: GO is an open-source programming language developed at Google. It is also known as Golang. This language is designed primarily for system programming.

2. What are the advantages of the Go programming language?
Answer: The advantages of Go programming language are as follows:

• Go is fast and compiles very quickly.
• It supports concurrency at the language level.
• It has Garbage collection.
• It supports various safety features and CSP-style concurrent programming features.
• Strings and Maps are built into the language.
• Functions are first class objects in this language.

3. What is the default value of a local variable in Go?
Answer: The default value of a local variable is as its corresponding 0 value.

4. What are the operators in Golang?
Answer:

• Arithmetic operators
• Bitwise operators
• Relational operators
• Logical operators
• Assignment operators
• Misc operators

5. What data types does Golang use?
Answer: Golang uses the following types:

• Method
• Boolean
• Numeric
• String
• Array
• Slice
• Struct
• Pointer
• Function
• Interface
• Map
• Channel

6. What are string literals in Golang?
Answer: String literals represent constants obtained from concatenating a sequence of characters. There are two forms:

• Raw string literals: The value of raw string literals are character sequence between back quotes ‘‘. The value of a string literal is the string composed of the uninterrupted character between quotes.
• Interpreted string literals: It is represented between double quotes ““. The text between the double quotes which may not contain newlines, forms the value of the literal.

7. What is the static type declaration of a variable in Golang?
Answer: Static type variable declaration gives confirmation to the compiler that there is one variable existing with the given kind and name so the compiler continues for an additional compilation without requiring total insight concerning the variable. A variable declaration holds its importance at the moment of compilation only, the compiler requires an actual variable declaration at the moment of connecting to the program.

8. What are built-in supports in Golang?
Answer:

• Web server: http/net
• Container: heap/container list/ container
• Cryptography: crypto md5/ crypto
• Database: sql/database
• Compression: gzip/compress

9. What are the decision-making statements in Golang?
Answer: There are 4 decision-making statements in Golang which are:

• if statement: used to decide whether certain statements will be executed or not
• if-else statement: if a certain condition is true only then it will execute a block if it is not true then it won’t execute the block of code
• Nested-if statement: nested if means if condition inside another if condition
• if-else-if ladder: Here, a user can choose among various options. The if statements are executed of top-down. As early as one of the states controlling the if is correct, the statement compared with that if is executed, and the remaining ladder is bypassed. If none of the conditions is correct, then the last else statement will be executed.

10. What is the GoROOT variable in Golang?
Answer: GoROOT is a variable that determines wherever your Go SDK is located. You do not require to modify this variable except you plan to use various Go versions. GoPATH is a variable that determines the root of your workspace.

11. What is the channel in Golang?
Answer: A channel is a communication medium through which a Goroutine communicates with different Goroutine and this communication is lock-free. Practically, in other words, a channel is a method that enables an individual Goroutine to send data to a different Goroutine.

12. What's the difference between unbuffered and buffered channels?
Answer: For the buffered channel, the sender will block when there is an empty slot of the channel, while the receiver will block on the channel when it's empty whereas, in an unbuffered channel, the sender will block the channel until the receiver receives the channel's data. Simultaneously, the receiver will also block the channel until the sender sends data into the channel.

13. Which is safer for concurrent data access? Channels or Maps?
Answer:

• Channels are safe for concurrent access because they have blocking/locking mechanisms that do not let goroutines share memory in the presence of multiple threads.
• Maps are unsafe because they do not have locking mechanisms. While using maps, we have to use explicit locking mechanisms like mutex for safely sending data through goroutines.

14. What do you understand by Shadowing in Go?
Answer: Shadowing is a principle when a variable overrides a variable in a more specific scope. This means that when a variable is declared in an inner scope having the same data type and name in the outer scope, the variable is said to be shadowed. The outer variable is declared before the shadowed variable.

15. How can you check a variable type at runtime in Golang?
Answer: There’s a special switch in Go that is dedicated to checking variable types during runtime, often referred to as the “type switch”.

16. Is Golang Multithreaded?
Answer: Yes, Golang is multithreaded and it is possible to do multi-threaded concurrency with Golang.

17. How many threads can Golang use?
Answer: Golang can use up to 10000 threads, but after that amount of threads is reached the program blocks the system call.

18. Is Golang compiled or interpreted?
Answer: Golang is a compiled language. It has the potential to compile files very fast, and the resulting binary seems to be very small.

19. What are Golang pointers?
Answer: Go Pointers are those variables that hold the address of any variables. Due to this, they are called special variables. Pointers support two operators.

20. What do you understand by the scope of variables in Go?
Answer: The variable scope is defined as the part of the program where the variable can be accessed. Every variable is statically scoped (meaning a variable scope can be identified at compile time) in Go which means that the scope is declared at the time of compilation itself. There are two scopes in Go, they are:

• Local variables - These are declared inside a function or a block and is accessible only within these entities.
• Global variables - These are declared outside function or block and is accessible by the whole source file.

In summary, everything that you need to know has been listed above and it is now upon you to make it bi on your interview day. Just ensure that you remember all the answers and the interview will turn out to be just a walk in the park. Trust yourself that you will excel. Wish you the best of luck in your interview.