[Solved] This code tries to reopen the Integer class to add a method double. What is wrong?class Integer def double self * 2 end end puts 5.double() | Ruby

Ruby - Class Methods and Variables

This code tries to reopen the Integer class to add a method double. What is wrong?

class Integer
  def double
    self * 2
  end
end

puts 5.double()

AMethod double should be defined as a class method, not instance method.

BYou cannot reopen built-in classes like Integer.

CNothing is wrong; it will print 10.

DThe method double uses wrong syntax for multiplication.

Step-by-Step Solution

Solution:

Step 1: Check if reopening Integer is allowed
Ruby allows reopening built-in classes like Integer to add instance methods.
Step 2: Verify method and usage
Method double multiplies self by 2, and calling 5.double() returns 10.
Final Answer:
Nothing is wrong; it will print 10. -> Option C
Quick Check:
Reopen Integer + instance method works = 10 output [OK]

Quick Trick: Reopen built-in classes freely; instance methods work [OK]

Common Mistakes:

Master "Class Methods and Variables" in Ruby

9 interactive learning modes - each teaches the same concept differently

More Ruby Quizzes

This code tries to reopen the Integer class to add a method double. What is wrong?