GO Lang Most asked Interview questions

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1. Go Basics (Syntax & Fundamentals)

1. What are the key features of Go?
2. How is Go different from other programming languages like Python or Java?
3. How do you declare variables in Go?
4. What are the different data types in Go?
5. What is the difference between var and := in Go?
6. What is a constant in Go, and how do you declare it?
7. How does Go handle type inference?
8. What is the zero value in Go?
9. What is the iota keyword in Go?
10. How do you perform string concatenation in Go?

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2. Control Structures & Flow

11. What looping constructs does Go support?
12. What is the difference between break, continue, and goto?
13. How do you use a switch statement in Go?
14. Does Go support while or do-while loops?
15. How do you iterate over an array, slice, or map in Go?

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3. Functions and Methods

16. How do you declare and call a function in Go?
17. What are multiple return values in Go?
18. What are named return values in Go?
19. What are variadic functions in Go?
20. Can you assign functions to variables in Go?
21. How does Go handle function arguments (pass by value or reference)?
22. What is a closure in Go?
23. What is a higher-order function in Go?
24. How do you return an anonymous function in Go?
25. Can Go functions have default arguments?

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4. Arrays, Slices, and Maps

26. What is the difference between arrays and slices in Go?
27. How do you declare and initialize slices in Go?
28. How do you add elements to a slice?
29. What is the capacity of a slice in Go?
30. How do you copy a slice?
31. What is the difference between make() and new() in Go?
32. How do you declare and iterate over a map in Go?
33. What happens if you access a non-existent key in a map?
34. How do you delete an element from a map in Go?
35. Can a map key be a struct in Go?

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5. Structs and Interfaces

36. What is a struct in Go?
37. How do you create an instance of a struct?
38. What is the difference between a struct and a class?
39. How do you define methods on a struct?
40. How do you implement an interface in Go?
41. What is an empty interface (interface{}) in Go?
42. What is type assertion in Go?
43. What is type switching in Go?
44. How does Go handle multiple interfaces?
45. Can an interface have fields in Go?

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6. Concurrency in Go

46. What are goroutines in Go?
47. How do you start a goroutine?
48. What is the difference between goroutines and threads?
49. What are channels in Go?
50. What is the difference between buffered and unbuffered channels?
51. How do you close a channel in Go?
52. What happens when you send data to a closed channel?
53. How do you use the select statement with channels?
54. What is a WaitGroup in Go?
55. What is a Mutex in Go, and when would you use it?

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7. Error Handling

56. How does Go handle errors?
57. What is the error interface in Go?
58. What is fmt.Errorf() used for?
59. How do you create custom errors in Go?
60. What is the recover() function in Go?
61. How do you use defer in Go?
62. What is the difference between panic and recover?
63. When should you use panic() in Go?
64. How can you propagate an error up the call stack?
65. How do you handle errors gracefully in Go?

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8. File Handling and I/O

66. How do you read and write files in Go?
67. What is the difference between os.Open() and ioutil.ReadFile()?
68. How do you create a new file in Go?
69. How do you write data to a file in Go?
70. How do you read a file line by line in Go?
71. How do you check if a file exists in Go?
72. How do you delete a file in Go?
73. What is the purpose of defer when handling files?
74. How do you append to a file instead of overwriting it?
75. How do you read a JSON file into a struct?

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9. Packages and Modules

76. What is a package in Go?
77. How do you create a custom package in Go?
78. How do you import a package in Go?
79. What is the purpose of init() function in Go?
80. What is go mod and how does it work?
81. What is the difference between go get and go mod tidy?
82. How do you manage dependencies in Go?
83. What is the GOPATH environment variable?
84. What is the difference between internal and vendor directories?
85. How do you make a package private in Go?

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10. Web Development with Go

86. How do you create a basic HTTP server in Go?
87. What is the net/http package used for?
88. How do you handle GET and POST requests in Go?
89. How do you parse query parameters in Go?
90. What is the http.ServeMux in Go?
91. How do you create middleware in Go?
92. What is gorilla/mux, and why is it useful?
93. How do you handle JSON requests and responses in Go?
94. How do you use WebSockets in Go?
95. How do you secure an HTTP server in Go?

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11. Testing and Debugging

96. How do you write a unit test in Go?
97. What is table-driven testing in Go?
98. How do you run tests in Go?
99. How do you benchmark code in Go?
100. How do you debug a Go program?