This document discusses recursion in Python. It defines recursion as a function calling itself. It notes that recursion allows looping through data to reach a result. The advantages are that recursive functions can break problems into simpler sub-problems and generate sequences more easily than iteration. Disadvantages include logic being hard to follow and recursive calls using more memory and time. There are two types of recursion: direct and indirect. A base case is needed to stop infinite recursion. The recursion limit depends on the operating system. Code snippets demonstrate calculating a sum recursively and tracking the recursion steps.

1. BY: ABHISHEK BHARDWAJ
PGT- COMPUTER SCIENCE

2. What is the function recursion in Python?
 Python also accepts function recursion, which means
a defined function can call itself.
 It means that a function calls itself.
 This has the benefit of meaning that you can loop
through data to reach a result.

3. Advantages of Recursion :
 Recursive functions make the code look clean and
elegant (Attractive).
 A complex task can be broken down into simpler sub-
problems using recursion.
 Sequence generation is easier with recursion than
using some nested iteration.
Disadvantages of Recursion :
 Sometimes the logic behind recursion is hard to follow
through.
 Recursive calls are expensive (inefficient) as they take
up a lot of memory and time.
 Recursive functions are hard to debug.

4.  Recursion are mainly of two types :
 When a function calls itself from within itself is
called direct recursion.
 When more than one function, call, one another
mutually is called indirect recursion.

5.  A recursion which leads to a infinite recursion is
termed as insensible recursion.
CODE SNIPPET :
1
2 3
Insensible Function Call
Base Case is a Condition/ Case, where, recursion stops.
To implement a recursion program, we have to prepare the base case first.
Recursion program implemented with Base Case is called right/ sensible

6.  Recursion limit is platform (Operating System) dependent.
CODE SNIPPET :
OUTPUT :

7. CODE SNIPPET :
OUTPUT :
BASE CASE :
4
3
2
1
Start of Recursion
Base Case
Recursion
1
2 3
4+Sum(3)
6
3+Sum(2)
3
2+Sum(1)
1
RECURSION STEPS:
3
6
10
Base Case