some solutions for projects on odin project

caesar_cipher.rb

@@ -0,0 +1,22 @@
+### CAESAR CIPHER
+Alphabet = 'abcdefghijklmnopqrstuvwxyz'
+
+def caesar_cipher(input, shift)
+  unless shift.is_a? Numeric and input.is_a? String
+    raise TypeError("Receive invalid input")
+  end
+
+  input.downcase!
+
+  array_from_input = Array.new(input.length)
+  result = ''
+  for i in 0..(input.length - 1)
+    start = Alphabet.index(input[i])
+    after_shift = start ? Alphabet[(start + shift % 26)] : -1
+    result += after_shift == -1 ? input[i] : Alphabet[after_shift]
+  end
+
+  result
+end
+
+print caesar_cipher("Doing stuff with Ruby", 5)