MCQs on Ruby Syntax and Basics | Ruby

Explore essential Ruby syntax rules, data types, variables, constants, and the importance of comments in this guide. Understand how to write clean, effective Ruby code while leveraging its powerful features.

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MCQs on Ruby Syntax and Basics

Section 1: Ruby Syntax Rules (8 Questions)

1. Which of the following is the correct syntax for defining a method in Ruby?
   • a) def method_name()
   • b) method_name() = def
   • c) method method_name()
   • d) function method_name()
2. In Ruby, what symbol is used to denote the start of a comment?
   • a) //
   • b) #
   • c) <!--
   • d) /*
3. What is the correct syntax for creating a class in Ruby?
   • a) class ClassName {}
   • b) class ClassName do end
   • c) class ClassName()
   • d) class ClassName() do end
4. How is an array defined in Ruby?
   • a) []
   • b) array[]
   • c) {}
   • d) new array
5. What is the correct way to concatenate strings in Ruby?
   • a) string1 + string2
   • b) string1.concat(string2)
   • c) string1 . join string2
   • d) Both a and b
6. Which keyword is used to define a block in Ruby?
   • a) function
   • b) block
   • c) do
   • d) yield
7. How do you exit a loop prematurely in Ruby?
   • a) end
   • b) stop
   • c) exit
   • d) break
8. In Ruby, what will the statement 5.times { print "Hello" } output?
   • a) “Hello” five times
   • b) “5 times Hello”
   • c) Error
   • d) “Hello” printed once

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Section 2: Comments and Documentation (6 Questions)

9. What is the purpose of comments in Ruby?
   • a) To speed up the code execution
   • b) To explain and document the code
   • c) To define variables
   • d) To create loops
10. Which type of comment is used for single-line comments in Ruby?
    • a) #
    • b) //
    • c) /*
    • d) <!--
11. How do you write a multi-line comment in Ruby?
    • a) =begin and =end
    • b) /* */
    • c) //
    • d) { }
12. What is the correct syntax for adding a documentation comment for a method in Ruby?
    • a) # This is a comment
    • b) /* This is a comment */
    • c) =begin This is a comment =end
    • d) # Method description
13. Which of the following is not a valid comment in Ruby?
    • a) # A single-line comment
    • b) /* Multi-line comment */
    • c) // Invalid comment
    • d) =begin Multi-line comment =end
14. What is the purpose of the YARD tool in Ruby?
    • a) To optimize the code
    • b) To compile Ruby code
    • c) To generate documentation from comments
    • d) To run Ruby code in a virtual environment

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Section 3: Variables and Constants (8 Questions)

15. Which of the following is the correct syntax to declare a variable in Ruby?
    • a) variable_name = value
    • b) value = variable_name
    • c) variable_name : value
    • d) let variable_name = value
16. What is the naming convention for a local variable in Ruby?
    • a) Starts with a capital letter
    • b) Starts with a lowercase letter
    • c) Can contain spaces
    • d) Starts with an underscore
17. Which of the following correctly defines a constant in Ruby?
    • a) const PI = 3.14
    • b) Constant PI = 3.14
    • c) PI = 3.14
    • d) constant PI = 3.14
18. In Ruby, how is a global variable defined?
    • a) $variable_name
    • b) @variable_name
    • c) @@variable_name
    • d) variable_name$
19. What is the scope of a class variable in Ruby?
    • a) Accessible across all classes
    • b) Accessible only within the class
    • c) Accessible across all objects of a class
    • d) Not used in Ruby
20. What is the behavior of a constant in Ruby if you attempt to change its value?
    • a) It throws an error
    • b) It updates the value without any issue
    • c) It triggers a warning
    • d) It reverts to its original value
21. What is the symbol used to denote an instance variable in Ruby?
    • a) @
    • b) $
    • c) @@
    • d) #
22. What happens when you reference a variable that has not been initialized in Ruby?
    • a) It throws an error
    • b) It returns nil
    • c) It returns a warning
    • d) It is automatically initialized to false

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Section 4: Data Types (8 Questions)

23. Which of the following is a valid number data type in Ruby?
    • a) Integer
    • b) Float
    • c) Rational
    • d) All of the above
24. What is the result of the expression 5 / 2 in Ruby?
    • a) 2.5
    • b) 2
    • c) 3
    • d) Error
25. What is the Ruby string interpolation syntax?
    • a) #{}
    • b) <<
    • c) ()
    • d) []
26. Which of the following is used to represent booleans in Ruby?
    • a) true and false
    • b) 1 and 0
    • c) True and False
    • d) Yes and No
27. Which of the following is a symbol in Ruby?
    • a) "symbol"
    • b) :symbol
    • c) symbol()
    • d) symbol[]
28. What is the difference between a string and a symbol in Ruby?
    • a) Strings are mutable, symbols are immutable
    • b) Symbols are mutable, strings are immutable
    • c) Strings are objects, symbols are primitives
    • d) There is no difference
29. What method is used to convert a number into a string in Ruby?
    • a) to_string()
    • b) str()
    • c) to_s()
    • d) stringify()
30. How would you check if a variable is an integer in Ruby?
    • a) variable.is_integer?
    • b) variable.kind_of?(Integer)
    • c) variable.is_a?(Integer)
    • d) Both b and c

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Answer Key

Qno	Answer (Option with the text)
1	a) def method_name()
2	b) #
3	b) class ClassName do end
4	a) []
5	d) Both a and b
6	c) do
7	d) break
8	a) “Hello” five times
9	b) To explain and document the code
10	a) #
11	a) =begin and =end
12	d) # Method description
13	c) // Invalid comment
14	c) To generate documentation from comments
15	a) variable_name = value
16	b) Starts with a lowercase letter
17	a) const PI = 3.14
18	a) $variable_name
19	c) Accessible across all objects of a class
20	c) It triggers a warning
21	a) @
22	b) It returns nil
23	d) All of the above
24	b) 2
25	a) #{}
26	a) true and false
27	b) :symbol
28	a) Strings are mutable, symbols are immutable
29	c) to_s()
30	d) Both b and c