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Question-1. What is Lua?
Answer-1: Lua is a lightweight, high-level, multi-paradigm scripting language designed for embedded use.
Question-2. Who developed Lua and when?
Answer-2: Lua was developed by Roberto Ierusalimschy, Luiz Henrique de Figueiredo, and Waldemar Celes in 1993.
Question-3. What is Lua primarily used for?
Answer-3: Lua is used for embedded systems, game development, and extending applications.
Question-4. What type of programming paradigms does Lua support?
Answer-4: Lua supports procedural, object-oriented, and functional programming paradigms.
Question-5. What are the key features of Lua?
Answer-5: Lightweight, fast, embeddable, dynamic typing, and garbage collection.
Question-6. How do you declare a variable in Lua?
Answer-6: Variables are declared with local or globally by simply assigning a value. Example: local x = 10.
Question-7. How do you write a comment in Lua?
Answer-7: Use -- for single-line comments and --[[ ]] for multi-line comments.
Question-8. What is a table in Lua?
Answer-8: A table is a data structure used to implement arrays, dictionaries, and other data types.
Question-9. How do you create a table in Lua?
Answer-9: Use {}. Example: local t = {1, 2, 3}.
Question-10. What is the difference between pairs() and ipairs()?
Answer-10: pairs() iterates over all key-value pairs, ipairs() iterates over numeric indices only.
Question-11. What is the default data type of Lua variables?
Answer-11: Lua variables are dynamically typed, meaning their type is determined by the value assigned.
Question-12. How do you concatenate strings in Lua?
Answer-12: Use ... Example: local result = "Hello" .. " World".
Question-13. What are metatables in Lua?
Answer-13: Metatables define the behavior of tables when certain operations are performed on them.
Question-14. How do you set a metatable for a table?
Answer-14: Use setmetatable(). Example: setmetatable(t, mt).
Question-15. What are metamethods in Lua?
Answer-15: Metamethods are special keys in metatables that define behavior for operators like + or indexing.
Question-16. How does garbage collection work in Lua?
Answer-16: Lua's garbage collector automatically manages memory by reclaiming unused objects.
Question-17. What is a coroutine in Lua?
Answer-17: A coroutine is a lightweight thread allowing functions to yield and resume execution.
Question-18. How do you create a coroutine in Lua?
Answer-18: Use coroutine.create(function) or coroutine.wrap(function).
Question-19. What is the purpose of require() in Lua?
Answer-19: require() loads and runs a module.
Question-20. What is the difference between require() and dofile()?
Answer-20: require() caches loaded modules; dofile() always executes the file.
Question-21. How do you declare a function in Lua?
Answer-21: Use function keyword. Example: function add(a, b) return a + b end.
Question-22. Can Lua functions return multiple values?
Answer-22: Yes, Lua functions can return multiple values. Example: return a, b.
Question-23. What is a closure in Lua?
Answer-23: A closure is a function that captures variables from its surrounding scope.
Question-24. How do you handle errors in Lua?
Answer-24: Use pcall() or xpcall() for protected calls.
Question-25. What is the difference between pcall() and xpcall()?
Answer-25: pcall() runs a function in protected mode; xpcall() provides a custom error handler.
Question-26. What are Lua's standard data types?
Answer-26: Nil, boolean, number, string, userdata, function, thread, and table.
Question-27. What is nil in Lua?
Answer-27: nil represents the absence of a value or a non-existent key in a table.
Question-28. How do you handle modules in Lua?
Answer-28: Use module() (deprecated) or return table at the end of the module file.
Question-29. What is load() in Lua?
Answer-29: load() compiles a Lua chunk from a string and returns it as a function.
Question-30. How do you iterate over a table in Lua?
Answer-30: Use for k, v in pairs(table) do.
Question-31. How do you find the length of a table in Lua?
Answer-31: Use #table.
Question-32. What is os library in Lua?
Answer-32: The os library provides functions for date, time, and operating system operations.
Question-33. How do you format strings in Lua?
Answer-33: Use string.format(). Example: string.format("Value: %d", value).
Question-34. How do you split a string in Lua?
Answer-34: Use string.gmatch() or custom logic.
Question-35. What is the purpose of math library in Lua?
Answer-35: The math library provides mathematical functions like math.sin, math.floor, etc.
Question-36. How do you perform file operations in Lua?
Answer-36: Use io library. Example: io.open(), file:read(), file:write().
Question-37. How do you read user input in Lua?
Answer-37: Use io.read(). Example: local input = io.read("*line").
Question-38. What is debug library in Lua?
Answer-38: The debug library provides tools for introspection and debugging, like debug.traceback().
Question-39. How do you set a custom error message?
Answer-39: Use error(). Example: error("Custom error message").
Question-40. What is the difference between tonumber() and tostring()?
Answer-40: tonumber() converts to a number; tostring() converts to a string.
Question-41. How do you define an object in Lua?
Answer-41: Use tables and metatables to simulate object-oriented programming.
Question-42. How do you use inheritance in Lua?
Answer-42: Use metatables with the __index field pointing to the parent table.
Question-43. What is the io library in Lua?
Answer-43: The io library handles file input and output operations.
Question-44. What is the purpose of next() in Lua?
Answer-44: next() iterates over table keys and values.
Question-45. What does type() function do in Lua?
Answer-45: type() returns the data type of a given value.
Question-46. What is the maximum number size in Lua?
Answer-46: Lua uses double-precision floating-point numbers, so it's platform-dependent.
Question-47. What is the purpose of select() in Lua?
Answer-47: select() retrieves arguments passed to a function beyond a specified index.
Question-48. How do you check if a key exists in a table?
Answer-48: Use table[key] ~= nil.
Question-49. What is the purpose of require "strict" in Lua?
Answer-49: It ensures that all variables are declared before use.
Question-50. How do you exit a Lua script?
Answer-50: Use os.exit().
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