You want to create a module MathOps with a module method double that doubles a number, and also allow classes to include MathOps to get an instance method triple that triples a number. How would you define this?
Amodule MathOps
def double(x)
x * 2
end
def self.triple(x)
x * 3
end
end
Bmodule MathOps
def self.double(x)
x * 2
end
def triple(x)
x * 3
end
end
Cmodule MathOps
def self.double(x)
x * 2
end
def self.triple(x)
x * 3
end
end
Dmodule MathOps
def double(x)
x * 2
end
def triple(x)
x * 3
end
end
Step-by-Step Solution
Solution:
Step 1: Define module method for doubling
Use def self.double(x) to create a module method callable on MathOps.
Step 2: Define instance method for tripling
Define def triple(x) as an instance method to be available when included in classes.
Final Answer:
Use self.double for module method and triple without self for instance method -> Option B
Quick Check:
Module method with self, instance method without = A [OK]
Quick Trick:Use self for module methods, normal defs for instance methods [OK]
Common Mistakes:
Defining both methods as module methods
Defining both as instance methods
Mixing up self usage
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