Even or Odd (8kyu) [Ruby]

This is a very popular kata. Let's solve it!

Chek kata on Codewars

Description:

Create a function (or write a script in Shell) that takes an integer as an argument and returns "Even" for even numbers or "Odd" for odd numbers.

Solution 1

Let's use Modulo operator (%) operator. It returns the remainder left over when one operand is divided by a second operand. It always takes the sign of the dividend.

4 % 2 // 0
3 % 2 // 1

If the number is even it returns 0 and if the number is odd it returns 1. Which converts to false or true accordingly.

def even_or_odd(number)
  (number % 2 == 0) ? "Even" : "Odd"
end

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Solution 2

Alternatively, we can create an array with 'Even' and 'Odd' values and return the first or second element.

def even_or_odd(number)
  ['Even', 'Odd'][number % 2]
end

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Solution 3

Using even?/odd? methods.

def even_or_odd(number)
  number.even? ? "Even" : "Odd"
end