You have a method that accepts any object and should behave differently if the object is a String or a Numeric (including Integer and Float). Which Ruby code correctly uses is_a? or kind_of? to check this?
Aif obj.is_a?(String)
puts "It's a string"
elsif obj.is_a?(Numeric)
puts "It's a number"
else
puts "Unknown type"
end
Bif obj.kind_of?(String)
puts "It's a string"
elsif obj.kind_of?(Integer)
puts "It's a number"
else
puts "Unknown type"
end
Cif obj.is_a?(String)
puts "It's a string"
elsif obj.kind_of?(Float)
puts "It's a number"
else
puts "Unknown type"
end
Dif obj.is_a?(Object)
puts "It's a string"
elsif obj.is_a?(Numeric)
puts "It's a number"
else
puts "Unknown type"
end
Step-by-Step Solution
Solution:
Step 1: Understand class hierarchy
Numeric is a superclass of Integer and Float, so checking is_a?(Numeric) covers all number types.
Step 2: Analyze each option
if obj.is_a?(String)
puts "It's a string"
elsif obj.is_a?(Numeric)
puts "It's a number"
else
puts "Unknown type"
end correctly checks for String and then Numeric. if obj.kind_of?(String)
puts "It's a string"
elsif obj.kind_of?(Integer)
puts "It's a number"
else
puts "Unknown type"
end checks Integer only, missing Float. if obj.is_a?(String)
puts "It's a string"
elsif obj.kind_of?(Float)
puts "It's a number"
else
puts "Unknown type"
end checks only Float, missing Integer. if obj.is_a?(Object)
puts "It's a string"
elsif obj.is_a?(Numeric)
puts "It's a number"
else
puts "Unknown type"
end checks Object first, which is always true, so logic fails.
Final Answer:
Option A code correctly distinguishes String and all Numeric types -> Option A
Quick Check:
Use Numeric superclass to cover all numbers [OK]
Quick Trick:Check against Numeric to cover all number types [OK]
Common Mistakes:
Checking only Integer or Float separately
Using Object which is always true
Mixing is_a? and kind_of? incorrectly
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