Completed binary to decimal

lib/binary_to_decimal.rb

@@ -4,6 +4,25 @@
 # The least significant bit is at index 7.
 # Calculate  and return the decimal value for this binary number using
 # the algorithm you devised in class.
-def binary_to_decimal(binary_array)
-  raise NotImplementedError
+def binary_to_decimal(arr)
+  # Creating a blank new array the size of the original array
+  reversed = Array.new(arr.length)
+  # Starting decimal value at 0
+  decimal = 0
+  # Setting i to the last index of the array
+  i = arr.length - 1
+  arr.each do |number|
+    # Adding numbers to reversed aray
+    # Starting at end of original array
+    reversed[i] = number
+    # Decreasing value of i
+    i -= 1
+  end
+
+  # Going through each index of the reversed array
+  reversed.each_index do |index|
+    # If number is not 0, add 2 ** index to decimal
+    decimal += 2 ** index if reversed[index] != 0
+  end
+  return decimal
 end