Go Q&A: Comprehensive Questions and Solutions

Welcome to the Go Q&A repository! This repository is a comprehensive collection of questions and answers covering various aspects of the Go programming language. Whether you're a beginner learning Go or an experienced developer looking to expand your knowledge, this repository provides a valuable resource to test your understanding and discover solutions to common challenges faced by Go developers.

Why Go ?

Go, also known as Golang, is a powerful and modern programming language designed for efficiency, simplicity, and scalability. Here are some key reasons why Go is a great choice for building software projects:

1. Concurrency: Go's built-in concurrency primitives, such as goroutines and channels, make it easy to write efficient and scalable concurrent programs.

2. Performance: Go's statically typed nature and efficient runtime make it highly performant, enabling the development of fast and responsive applications.

3. Simplicity: Go has a simple and minimalistic syntax, which makes it easy to read, write, and maintain code. It emphasizes clarity and readability, reducing the cognitive load on developers.

4. Robust Standard Library: Go provides a rich standard library that covers a wide range of functionalities, enabling developers to quickly build robust and production-ready applications.

5. Strong Community: Go has a vibrant and supportive community of developers. The community actively contributes to the language and ecosystem, creating libraries, frameworks, and tools to enhance the development experience.

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Questions

Q1. In Go, can a struct implement multiple interfaces?

Q2. What is an interface in Go?

Q3. What is the purpose of the defer keyword in Go?

Q4. How do you handle errors in Go?

Q5. Can you create an instance of an interface in Go?

Q6. Can a function in Go take an interface as a parameter?

Q7. Can a value satisfy an interface in Go without explicitly implementing it?

Q8. How do you perform unit testing in Go?

Q9. Can an interface be used as a return type in Go?

Q10. How do you check if a value is of a specific interface type in Go?

Q11. Can you have a variable of interface type in Go?

Q12. What do you need for two functions to be the same type?

Q13. Which type is a rune an alias for?

Q14. What is the value of Read?

Q15. What would happen if you attempted to compile and run this Go program?

Q16. What restriction is there on the type of var to compile this i := myVal.(int)?

Q17. How is the behavior of t.Fatal different inside a t.Run?

Q18. What does log.Fatal do?

Q19. What is the common way to have several executables in your project?

Q20. If you iterate over a map in a for range loop, in which order will the key:value pairs be accessed?

Q21. What will this code print?

Q22. What symbol is used to declare a single-line comment in Go?

Q23. Which of the following is a valid way to declare a variable in Go?

Q24. In Go, what is the correct way to define a function named add that takes two integer parameters and returns their sum?

Q25. How do you import a package in Go?

Q26. What is the zero value of a boolean variable in Go?

Q27. Which data type is used for storing single characters in Go?

Q28. Which statement is used to create a loop in Go?

Q29. In Go, how do you find the length of a slice?

Q30. What is the correct syntax for declaring and initializing an empty map in Go?

Q31. Which of the following statements is used to create a new instance of a structure in Go?

Q32. What is the result of the expression 5 / 2 in Go?

Q33. How do you declare and initialize a constant in Go?

Q34. In Go, what is the purpose of the panic function?

Q35. Which of the following is a correct way to define an empty slice in Go?

Q36. What is the purpose of the range keyword in a for loop in Go?

Q37. Which of the following is a valid way to concatenate two strings in Go?

Q38. In Go, how do you declare a pointer to an integer variable?

Q39. What is the purpose of the select statement in Go?

Q40. What is the correct way to create an anonymous function (a function without a name) in Go?

Q41. In Go, what is the purpose of the ... syntax in a function parameter?

Q1. In Go, can a struct implement multiple interfaces?

• Yes, Go allows a struct to implement multiple interfaces.
• No, Go only supports single interface implementation for a struct.
• It depends on the visibility of the struct's fields.
• Multiple interface implementation is not supported in Go.

Q2. What is an interface in Go?

• An interface is a type that represents a collection of methods.
• An interface is a way to define constants in Go.
• An interface is a type used for casting between different types.
• An interface is a keyword used for importing external packages in Go.

Q3. What is the purpose of the defer keyword in Go?

• To define a constant value.
• To perform error handling in Go.
• To specify a function that is executed when the program terminates.
• To schedule a function call to be executed when the surrounding function returns.

Q4. How do you handle errors in Go?

• By using try-catch blocks.
• By using the panic keyword.
• By returning error values from functions and checking them explicitly.
• Go automatically handles errors without explicit coding.

Q5. Can you create an instance of an interface in Go?

• Yes, an instance of an interface can be created.
• No, interfaces are only used for type checking.
• Interfaces are implicitly instantiated when implementing types.
• Interfaces can only be used as pointers in Go.

Q6. Can a function in Go take an interface as a parameter?

• No, functions can only take concrete types as parameters.
• Yes, functions can take interfaces as parameters, enabling polymorphism.
• Interfaces can only be used as return types for functions.
• Functions in Go can only accept pointer receivers for interfaces.

Q7. Can a value satisfy an interface in Go without explicitly implementing it?

• Yes, a value can implicitly satisfy an interface if it has all the methods defined by the interface.
• No, interface satisfaction in Go requires explicit implementation.
• Implicit interface satisfaction is only possible for built-in types in Go.
• Interface satisfaction in Go is based on the type hierarchy and cannot be achieved implicitly.

Q8. How do you perform unit testing in Go?

• Go does not support unit testing.
• By using the testing package and writing test functions.
• By manually comparing expected and actual results in the code.
• By using third-party testing frameworks.

Q9. Can an interface be used as a return type in Go?

• Yes, interfaces can be used as return types to enable flexible typing.
• No, interfaces can only be used as parameters, not as return types.
• Return types in Go can only be concrete types, not interfaces.
• Interface return types are automatically inferred by the Go compiler.

Q10. How do you check if a value is of a specific interface type in Go?

• By using type assertions and checking the success of the assertion.
• By using the instanceof keyword.
• By using the implements function from the reflect package.
• [ ]Go automatically performs interface type checks at runtime.

Q11. Can you have a variable of interface type in Go?

• Yes, you can create variables of interface type in Go.
• No, interface types can only be used as function parameters.
• Interface variables are automatically created when assigning a value to an interface type.
• Interface variables can only be assigned to pointer

Q12. What do you need for two functions to be the same type?

• They should share the same signatures, including parameter types and return types.
• They should share the same parameter types but can return different types.
• All functions should be the same type.
• The functions should not be a first class type.

Q13. Which type is a rune an alias for?

• char
• byte
• int32
• string

Q14. What is the value of Read?

const (
  Write = iota
  Read
  Execute
)

• 0
• 1
• 2
• a random value

Q15. What would happen if you attempted to compile and run this Go program?

package main
var GlobalFlag string
func main() {
  print("["+GlobalFlag+"]")
}

• It would not compile because GlobalFlag was never initialized.
• It would compile and print [].
• It would compile and print nothing because "[" +nil+"]" is also nil.
• It would compile but then panic because GlobalFlag was never initialized.

Q16. What restriction is there on the type of var to compile this i := myVal.(int)?

• myVal must be an integer type, such as int, int64, int32, etc.
• myVal must be able to be asserted as an int.
• myVal must be an interface.
• myVal must be a numeric type, such as float64 or int64.

Q17. How is the behavior of t.Fatal different inside a t.Run?

• There is no difference.
• t.Fatal does not crash the test harness, preserving output messages.
• t.Fatal stops execution of the subtest and continues with other test cases.
• t.Fatal stops all tests and contains extra information about the failed subtest.

Q18. What does log.Fatal do?

• It raises a panic.
• It prints the log and then raises a panic.
• It prints the log and then safely exits the program.
• It exits the program.

Q19. What is the common way to have several executables in your project?

• Have a cmd directory and a directory per executable inside it.
• Comment out main.
• Use build tags.
• Have a pkg directory and a directory per executable inside it.

Q20. If you iterate over a map in a for range loop, in which order will the key:value pairs be accessed?

• In pseudo-random order that cannot be predicted
• In reverse order of how they were added, last in first out
• Sorted by key in ascending order
• In the order they were added, first in first out

Q21. What will this code print?

var i int8 = 120
i += 10
fmt.Println(i)

• -126
• 0
• NaN
• 130

Q22. What symbol is used to declare a single-line comment in Go?

• /*
• #
• //
• --

Q23. Which of the following is the easiest way to declare a variable in Go?

• let name = "mobin"
• var name string = "mobin"
• name = "mobin"
• name := "mobin"

Q24. In Go, what is the correct way to define a function named add that takes two integer parameters and returns their sum?

• function add(a int, b int) int { }
• func add(a int, b int) int { }
• def add(a int, b int) int { }
• procedure add(a int, b int) int { }

Q25. How do you import a package in Go?

• include "package_name"
• import "package_name"
• require "package_name"
• use "package_name"

Q26. What is the zero value of a boolean variable in Go?

• true
• 0
• false
• null

Q27. Which data type is used for storing single characters in Go?

• string
• rune
• character
• str

Q28. Which statement is used to create a loop in Go?

• for i := 0; i < 10; i++ { }
• while i < 10 { }
• loop (i < 10) { }
• repeat 10 times { }

Q29. In Go, how do you find the length of a slice?

• len(slice_name)
• size(slice_name)
• slice_name.length()
• slice_name.size()

Q30. What is the correct syntax for declaring and initializing an empty map in Go?

• var myMap map[string]int
• myMap := make(map[string]int)
• myMap = map[string]int{}
• myMap := map[string]int{}

Q31. Which of the following statements is used to create a new instance of a structure in Go?

• new(struct_name)
• create struct_name
• struct_name{}
• instantiate struct_name

Q32. What is the result of the expression 5 / 2 in Go?

• 2.5
• 2
• 2.0
• 2.5 (rounded down to 2)

Q33. How do you declare and initialize a constant in Go?

• const pi float64 = 3.14
• constant pi = 3.14
• pi := 3.14
• let pi = 3.14

Q34. In Go, what is the purpose of the panic function?

• To print a message to the console
• To stop the program immediately
• To handle errors gracefully
• To pause the program's execution temporarily

Q35. Which of the following is a correct way to define an empty slice in Go?

• emptySlice = []
• emptySlice := []
• emptySlice = make([]int, 0)
• emptySlice := make([]int, 0)

Q36. What is the purpose of the range keyword in a for loop in Go?

• It defines the range of loop iterations.
• It is used for error handling.
• It iterates over elements of a collection like an array or slice.
• It specifies the loop termination condition

Q37. Which of the following is a valid way to concatenate two strings in Go?

• str1.concat(str2)
• str1 + str2
• strings.Concat(str1, str2)
• strings.Join([]string{str1, str2}, "")

Q38. In Go, how do you declare a pointer to an integer variable?

• int* ptr = &variable
• var ptr *int = &variable
• pointer int = &variable
• ptr := &variable

Q39. What is the purpose of the select statement in Go?

• It is used for type assertions.
• It is used for channel communication.
• It is used to define custom data types.
• It is used for error handling.

Q40. What is the correct way to create an anonymous function (a function without a name) in Go?

• func() { }
• function() { }
• anonymous func() { }
• lambda() { }

Q41. In Go, what is the purpose of the ... syntax in a function parameter?

• It denotes a variadic function that can accept a variable number of arguments.
• It indicates a function that does not accept any arguments.
• It specifies a function that returns a variable number of values.
• It represents an array with a dynamic size.