GOlang Interview Questions

1. What is GOlang?

Ans: GOlang is a free programming language that Google has developed. It is also called GO programming. This language is mainly intended for system programming. GOlang allows us to create simple, efficient, and reliable software with ease. Programs are developed with packages whose properties make it possible to effectively manage dependencies.

2. What advantages does using Go have over other languages?

Ans: 

• In contrast to other languages that began as academic experiments, GOlang is designed in a pragmatic way. Each syntax decision and feature is designed to ease the life of the programmer.
• GOlang is enhanced for concurrency and functions well at scale.
• GOlang is much easier to read than other languages because of one standard code format.
• Automatic garbage collection is much more effective than Python or Java as it runs simultaneously next to the program.

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3. What are string literals?

Ans: String constant that resulted from the concatenation of a sequence of characters is represented as a String Literal. It has two forms:

• Raw string Literals: The value of the raw string literals is the sequence of characters enclosed in backquotes. The string literal value is the string made up of continuous characters in quotes.
• Interpreted String Literals: This is shown in double quotes. Text in double quotes cannot contain newlines, forming the literal value.

4. What is Workspace in GO?

Ans: Within a workspace, a GO code is to be kept. A workspace is a hierarchy of directories that have three directories in root: src, pkg, and bin.

• Src holds the GO source files arranged as packages.
• Pkg includes package objects.
• Bin includes executable commands.

5. What are the data types in GOlang?

Ans: Data types in GOlang include:

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

6. What is the GOPATH environment variable?

Ans: GOPATH environment variable indicates where the workspace should be. This environment variable must be set during the development of the Go code.

7. What are packages in Go programming?

Ans: The packages are directories in the Go workspace, which contains Go source files. Each variable, kind of source file and function are stored in the associated packages. The program begins to function from package main. The program uses packages that have import paths "math/rand" and "fmt".

8. Explain the Go routine.

Ans: A goroutine is a method or function that runs simultaneously along with other goroutines using a special goroutine thread. Goroutine threads are lighter than standard threads. Most of the Golang programs use thousands of goroutines at the same time. For creating a Go routine, we need to add a 'go' keyword before the declaration of the function. By sending a signal channel, we can stop a goroutine. Regularly Goroutine polls that channel; when it detects the signal, it will quit.

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9. What are Go interfaces?

Ans: Interfaces are a means of specifying how an object behaves. Using the word "type" followed by the name and keyword interface, an Interface can be created. There are two things that define an interface.

• It is also called a type
• Set of methods

10. What is a rune?

Ans: A rune is a built-in type in Go and is called int32. In Go, the rune is the Unicode CodePoint. Regardless of the number of bytes the codepoint occupies, it may be represented by rune. A string doesn't have to be a rune sequence. We may convert from string to []rune, but they are not the same.

Intermediate level GOlang frequently asked Interview Questions:

11. What is a pointer, and when can we use it?

Ans: A pointer contains a value's memory address.
& creates a pointer for its operand.
* dereferences a pointer (it will expose the underlying value).
Pointers may be used for:

• Allows a function to transfer a value passed on to it directly.
• We can use pointers For performance enhancement in extreme cases. In some cases passing large data structures leads to inefficient data replication.
• To indicate an absence of value.

[Related Article: GOlang Vs C++]

12. How to verify a variable type at run time?

Ans: The best way to verify the type of a variable on runtime is using a type switch. It examines variables by type but not by value. Every Switch contains a minimum one 'case' that acts as the conditional Statement, and the 'default' case, it runs if neither case is true. For example, we can create a Type Switch which verifies whether the interface value 'i' includes the type 'string:' or 'int'.

13. Explain about dynamic type declaration of a variable.

Ans: Dynamic type declaration of a variable expects a compiler for interpreting the variable as per the value that is passed. The compiler does not require a variable to have the static type as an essential requirement.

14. Explain about Static type declaration of a variable.

Ans: Static type declaration of a variable gives the compiler some assurance that there is an existing variable with the type and name provided to allow the compiler to compile further without the need for full details of the variable. The variable declaration is only meaningful at the time of compilation; the compiler requires a real variable declaration during the program linkage.

15. Explain When do we use break Statement, continue Statement and go Statement.

Ans:

• Break Statement: It is used for the termination of the switch statement or for loop and transfers the execution to the next Statement following the switch statement or for a loop.
• Continue Statement: It makes the loop easier to jump the rest of its body and immediately reassess one's state before repeating it.
• Go Statement: Using this, the control is transferred to the labeled Statement.

16. How unbuffered and buffered channels differ?

Ans: In the case of an unbuffered channel, the sender blocks the channel till the data is reached to the receiver from the channel, while the receiver blocks the channel till the data is sent into the channel by the sender.

In comparison with the unbuffered channel, in the buffered channel, the sender will block when no empty slot is available.

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17. Explain the purpose of Type assertion.

Ans: Type conversion is intended to convert different types in GO. A type assertion will take an interface value and fetch a value of the explicitly specified type.

18. What's so unique about constants in Go?

Ans: Go's constants are unique. 

• Untyped Constants:  A constant in GOlang, unnamed or named, is untyped except if a type is explicitly given. For example, an untyped floating-point constant such as 4.5 may be used wherever a floating value is permitted. Untyped constants may be used to temporarily escape the strong type system of the Go system till they are evaluated in a type-demanding expression.
• Typed Constants: If we specify the type in the declaration explicitly they are called typed constants. All the flexibility available with untyped constants, such as allocating them to any of the compatible types or mixing them with the mathematical operations, are lost using typed constants. In general, we would need to declare a constant type only when absolutely necessary.

[Related Article: GOlang Vs Java]

19. How do you write multi-line strings in GO?

Ans: In GOlang, for writing a multi-line string, we use a raw string literal; here, the string will be delimited by backquotes instead of double-quotes.

Example: 

First line

Second line

Third line

20. How do arrays in Go work differently than C?

Ans: In GO, Array functionality is different than in C. 

• Arrays are the values; When we assign an array to another array, it will copy all the elements. 
• If we pass an array to a function, it will get a copy of that array rather than a pointer.
• The array size is part of its size.

GOlang frequently asked Interview Questions for Experienced:

21. Explain different methods in Go Programming Language.

Ans: In GOlang, there are various functions known as methods. In the syntax of method declaration, for representing the function's container, a 'receiver' is used. We can use this receiver to call the function using the "." operator.

22. What do you mean by modular programming?

Ans: Modular programming refers to the way of dividing the program into sub-programs like functions or modules in order to reach maximum efficiency.
The definition of more generic functions makes it easy to reuse features, like built-in library functions.

23. Explain about Lvalue and Rvalue.

24. In Go programming, how do we represent pointers?

Ans: In Go programming, a pointer will be represented by * followed by the stored value type. A pointer will hold the address of the variable.

Syntax: var a = 2 var s *int s = &a

              fmt.printf(‘a=%d”, *s)

Here a will be accessed by *s.

25. How will the syntax be in GOlang?

Ans: In Golang, the syntax will be defined by the Extended Backus-Naur Form.

• Production = production_name "=" [ Expression ]
• Expression = Alternative { "l" Alternative }
• Alternative = Term { Term }
• Term = Production_name l token [ "?"token] l Group l Option l Repetition
• Group = " ( "" Expression")"
• Option = " [ " Expression "" ]"
• Repetition = " {" Expression "}"

26. What are looping constructs?

Ans: Go has only a single loop construct: 'the for loop'. There are three components in the for loop separated by semicolons: Init statement, condition expression, and query statement.

• The Init statement that is executed prior to the start of the loop. This is usually a variable statement visible only in the for loop scope.
• The condition expression will be evaluated as a boolean prior to each iteration to decide whether the loop should continue or not.
• The query statement will be executed at the end of every iteration.

[Related Articles: GOlang Vs Python]

27. Is it possible to return multiple values from a function?

Ans: Yes, the Go function may return more than one value, each separated commas within the return statement.

28. How can we concatenate strings?

Ans: The simplest way for concatenating a string is using the concatenation operator (+). It enables us to add strings like how we add numeric values.

29. Does it make sense to use global variables in a program that implements Go routines?

Ans: Global variables are not recommended as they can be accessed by more than one routine at the same time, and it may lead to unexpected behavior resulting in arbitrary outcomes.

30. How can we perform inheritance?

Ans: In Golang, there is no inheritance as it will not support classes. But we can imitate the inheritance by using the composition for using an existing struct object for defining the new object's original behavior. When the new object is created, the features can be expanded beyond the original structure.

Conclusion:

All the questions listed above are frequently asked GOlang Interview Questions. They can help you to clear your interview on GOlang. However, if you notice any important question is not covered, you may drop a message to us in the comments. We will get back to you with the answer.