doctests and intro docstring added

sorts/pancake_sort.py

@@ -1,9 +1,25 @@
-"""Pancake Sort Algorithm."""
-# Only can reverse array from 0 to i
-
+"""
+This is a pure python implementation of the pancake sort algorithm
+For doctests run following command:
+python -m doctest -v pancake_sort.py
+or
+python3 -m doctest -v pancake_sort.py
+For manual testing run:
+python pancake_sort.py
+"""
 
 def pancake_sort(arr):
-    """Sort Array with Pancake Sort."""
+    """Sort Array with Pancake Sort.
+    :param arr: Collection containing comparable items
+    :return: Collection ordered in ascending order of items
+    Examples:
+    >>> pancake_sort([0, 5, 3, 2, 2])
+    [0, 2, 2, 3, 5]
+    >>> pancake_sort([])
+    []
+    >>> pancake_sort([-2, -5, -45])
+    [-45, -5, -2]
+    """
     cur = len(arr)
     while cur > 1:
         # Find the maximum number in arr
@@ -17,4 +33,6 @@ def pancake_sort(arr):
 
 
 if __name__ == '__main__':
-    print(pancake_sort([0, 10, 15, 3, 2, 9, 14, 13]))
+    user_input = input('Enter numbers separated by a comma:\n').strip()
+    unsorted = [int(item) for item in user_input.split(',')]
+    print(pancake_sort(unsorted))