def identify_class(obj)
    case obj
    when Hacker,Submission,TestCase,Contest
        puts "It's a #{obj.class}!"
    else
        puts "It's an unknown model"
    end
end

this works incase someone is looking for different solutions.

This problem statement is extremely misleading and needs to be rewritten.

As it is stated, we are lead to believe that Hacker, Submission, TestCase, and Constants are all separate classes inheriting from the same superclass. This means that the following solution should work:

    case obj
    when Hacker, Submission, TestCase, Contest
        puts "It's a #{obj.class}!"
    else
        puts "It's an unknown model"
    end

However, it fails test case 1. Moreover, some of the solutions listed below suggest that Hacker, Submission, TestCase, and Constant are really integer constants euqivalent to to 1, 2, 3, and 4.

Obviously, using integer constants instead of subclasses goes against the problem definition (as currently written). While it will work for basic solutions checking each class type separately, more elaborate solutions taking advantage of the obj.class value will fail. Moreover, testing one solution using subclasses and another using integer constants is extremely misleading; if our solution is expected to work for both situations, the problem statement should explicitly say so.

def identify_class(obj)
# write your case control structure here
case obj
when 1
puts "It's a Hacker!"
when 2
puts "It's a submission!"
when 3
puts "It's a TestCase!"
when 4
puts "It's a Contest!"
else
puts "It's an unknown model"
end
end
this code worked fine on IRB passing the input via method like so: identify_class(10), identify_class(3), etc But it's not working here.

Why does this work?

case obj

when Hacker, Submission, TestCase, Contest 

    puts "It's a #{obj.class}!"
else 

    puts"It's an unknown model"

end

When "k" == String it says false,

"k" === String is also false

what is the case logic in ruby?

I tried solving this by NOT using the case statement. I did something like this

def identify_class(obj)

if !obj.nil? && ['Hacker', 'Submission', 'TestCase', 'Contest'].include?(obj.class.to_s) puts("It\'s a #{obj.class}!") else puts("It\'s an unknown mode!") end
end

This works for general test case but fails for the hidden one. Any pointers what is causing this failure?

Hello Hackerrank,

On my system I am getting correct result with

[Hacker, Submission, TestCase, Contest].include?(obj.class) ? "It's a #{obj.class}!" : "It's an unknown model"

But while submitting it is giving no out put

Why isn't it case obj.class ?

This is my code, pass in the 1 test but not pass in the test 2. When Hacker{-truncate-} the expected output is "It's a Submission". Please, help me understand

def identify_class(obj) case obj when Hacker puts "It's a Hacker!" when Submission puts "It's a Submission!" when TestCase puts "It's a TestCase!" when Contest puts "It's a Contest!" else puts "It's an unknown model!" end end

For me, those two code are equivalent, but in practice the first one works, but the second doesn't, it falls into the default case. I was obliged to convert obj.class to string

if obj.class == Hacker or
		obj.class == Submission or
		obj.class ==TestCase or
		obj.class == Contest  
			puts "It's a #{obj.class.to_s}!"  
else
			puts "It's an unknown model" 
end

the second

case obj.class
        when Hacker,Submission,TestCase,Contest
          puts "It's a #{obj.class.to_s}!"  
else
          puts "It's an unknown model" 
end