[Solved] Identify the problem in this Ruby code using class variables:class A @@count = 0 def initialize @@count += 1 end def self.count @@count end end class B < A def initialize @@count += 10 end end A.... | Ruby

Ruby - Class Methods and Variables

Identify the problem in this Ruby code using class variables:

class A
  @@count = 0
  def initialize
    @@count += 1
  end
  def self.count
    @@count
  end
end

class B < A
  def initialize
    @@count += 10
  end
end

A.new
B.new
puts A.count

AThe code has a syntax error in class B definition.

BThe class variable @@count is not initialized properly.

CThe class variable @@count is shared and modified differently causing unexpected count.

DThe method self.count is missing a return statement.

Step-by-Step Solution

Solution:

Step 1: Analyze class variable usage in inheritance
Both classes A and B share the same @@count. A#initialize adds 1, B#initialize adds 10.
Step 2: Understand the effect on count
Creating A.new adds 1, then B.new adds 10, so total @@count becomes 11, which may be unexpected if counting instances separately.
Final Answer:
The class variable @@count is shared and modified differently causing unexpected count. -> Option C
Quick Check:
Shared @@count causes tricky bugs [OK]

Quick Trick: Shared @@ variables cause unexpected cross-class changes [OK]

Common Mistakes:

Thinking @@count is separate per class
Ignoring inheritance effect on @@ variables
Assuming initialize methods don't affect shared vars

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More Ruby Quizzes

Identify the problem in this Ruby code using class variables:

Step 1: Analyze class variable usage in inheritance

Step 2: Understand the effect on count

Final Answer:

Quick Check:

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