What are the advanced Golang interview questions and answers?

Golang, also known as Go, is a general-purpose open-source programming language built by Google. The popularity of Go rapidly increased, making it the preferred language for numerous developers because of its straightforwardness, ease of comprehension, effectiveness, and ability to execute multiple tasks simultaneously, which is known as concurrency.

If you want to land that Golang developer job you’ve been striving for, here are some of the best Golang interview questions to help you out.

10 Advanced Golang Interview Questions and Answers

1. How do you conduct testing in Golang?

Golang has built-in support for testing and provides a number of features to make it easier for you to write tests for your code. In Golang, tests are written as functions within a file with a “.go” extension and are executed using the ‘go test’ command. The test functions must be named with a specific naming convention, which begins with the word “Test”.

To run your tests, simply run the ‘go test’ command in the directory containing your test files. The ‘go test’ command will discover and run all of the tests in the directory and report the results.

2. What are built-in supports in Golang?

The following are Golang’s built-in supports:

  • Web Server: net/http
  • Database: database/sql
  • Container: container/list, container/heap
  • Compression: compress/ gzip
  • Cryptography: Crypto/md5 ,crypto/sha1

3. What is a rune in Golang?

In Golang, a ‘rune’ is an alias for the ‘int32′ data type and is used to represent a Unicode code point. In Go, a string is a sequence of Unicode code points, and a ‘rune’ is a single code point.

Golang uses the ‘rune’ data type, which is an alias for ‘int32‘, instead of the traditional ‘char’ data type, to represent characters. The reason behind this is that Golang uses Unicode as its default character encoding system, which encompasses a vast range of scripts including Latin, Greek, Chinese, and many others. In Unicode, each character has a distinct code point assigned to it, represented as an integer value. Therefore, a ‘rune’ in Go represents this unique Unicode code point as an integer.

4. What are some of the good error handling practices in Golang?

There are several good error handling practices you can us in Go:

  1. Use descriptive error messages that explain the problem clearly.
  2. Always check errors explicitly with an if statement, instead of relying on deferred calls or other mechanisms.
  3. Return errors as values and not as part of the function’s return value.
  4. Use the errors package to define and create error values.
  5. Wrap errors to provide more context and information about the error.
  6. Use panic and recover only in exceptional circumstances, and not for routine error handling.
  7. Use error codes sparingly, and prefer descriptive error messages over error codes.
  8. Test error handling code to ensure that it works correctly and provides the expected behavior.

Yes, you can format a string without printing in Golang using the “fmt.Sprintf” function. This function returns a formatted string but does not print it to the console or any output stream.

Here is an example:

an example of how to use fmt.Sprintf() to format a string without printing it in Go

In this example, we create a formatted string using fmt.Sprintf() and store it in the formattedString variable. We can then use this variable later in our code, or ignore it if we don’t need to use the formatted string again. The fmt.Println() function is used to print a different string to the console, so the formatted string created by fmt.Sprintf() is not printed.

6. What is the difference between GOROOT and GOPATH variables in Go?

The GOROOT and GOPATH variables in Golang are used to indicate the location of the Go standard library and the user’s Go workspace, respectively.

The GOROOT variable is set during the Go installation process and represents the root directory of the installation, where the standard library is kept.

On the other hand, the GOPATH variable is set by the user and points to the user’s Go workspace directory where the user’s Go projects and packages are stored.

Therefore, GOROOT specifies the location of the standard library while GOPATH specifies the location of the user’s Go workspace where the user’s projects and packages are kept.

7. What are ‘lvalue’ and ‘rvalue’ in Go?

In Go, an lvalue represents a memory location that can be identified with an expression like a variable or an array element. An rvalue, on the other hand, refers to an expression whose value can be assigned to an lvalue, and it can be a literal value or a function call’s result. For instance, if we consider x = 35 as an assignment statement, then x is an lvalue, and 35 is an rvalue.

8. Channels vs Maps: which one is safer for concurrent data access?

Channels provide a safe way to access data concurrently in Go because they utilize blocking and locking mechanisms that prevent multiple goroutines from sharing memory.

On the other hand, maps do not have built-in locking mechanisms and are thus considered unsafe for concurrent access potentially resulting in race conditions and other unpredictable behaviors. To prevent race conditions, synchronization mechanisms like locks must be used, which can complicate code and harm performance.

While maps can be used for concurrent data access with proper synchronization mechanisms, channels are a safer and more idiomatic way to handle concurrent communication and synchronization in Go.

9. What is shadowing in Golang?

In Go, and many other programming languages, variable shadowing happens when a variable is declared within a specific scope, such as an inner class, method, or decision block, with the same name as a variable declared in an outer scope. This results in the new variable “shadowing” or hiding the original variable within the inner scope, potentially leading to confusion and errors in code.

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