Category: Interview Questions

• Ruby has automatic garbage collection.
• It removes objects from memory that are no longer referenced.
• This prevents memory leaks.

If you call a method that doesn’t exist, Ruby calls method_missing.
You can override it to handle undefined methods.

class MyClass
  def method_missing(name, *args)
puts "Method #{name} is missing!"
  end
end

obj = MyClass.new
obj.hello   #

• Calls the method of the same name from parent class.

class Animal
  def speak
"Animal sound"
  end
end

class Dog < Animal
  def speak
super + " Woof!"
  end
end

puts Dog.new.speak
# Output: "Animal sound Woof!"

In Ruby, type is determined by behavior (methods), not class.
If an object can perform required actions, it can be used.

def make_it_talk(obj)
  obj.talk
end

class Dog
  def talk; puts "Woof!"; end
end

class Human
  def talk; puts "Hello!"; end
end

make_it_talk(Dog.new)   # Woof!
make_it_talk(Human.new) # Hello!

Ruby does not support multiple inheritance. Instead, it uses Mixins (via include keyword).

module Walkable
  def walk
puts "Walking..."
  end
end

class Person
  include Walkable
end

p = Person.new
p.walk   #

self represents the current object.

Inside a class → self refers to the object calling the method.

For class methods → self refers to the class itself.

• Block: Anonymous piece of code passed to methods.

3.times { puts "Hello" }

• Proc: Saved block that can be reused.

say = Proc.new { puts "Hi" }
say.call

• Lambda: Like a Proc but stricter about arguments.

l = ->(x) { x*x }
puts l.call(5) # 25

• == → checks equality of values.
• === → used in case statements and can behave differently depending on the class.

5 == 5      # true
(1..10) === 5  # true (range check)

Symbols are immutable, reusable names represented with a colon :.
They are faster and consume less memory than strings.

:age   # symbol
"age"  # string

• puts → prints output with newline.
• print → prints without newline.
• p → prints with debugging info (shows object’s raw form).

Example:

puts "Hello"   # Hello (new line)
print "Hello"  # Hello (no new line)
p "Hello"