The document discusses recursion, explaining that it refers to a function that can call itself to solve a problem until a specific condition is met. It highlights the advantages, such as efficiency and reduced coding, as well as disadvantages including the risk of infinite loops if not managed correctly. Additionally, the document provides examples of recursive functions, such as the factorial function and the Tower of Hanoi problem, illustrating the principles of recursion in action.

1. R e c u r s I o n
By Nalin Adhikari
© Nalin Adhikari

2. Contents
 Introduction
 Recursive Function
 Advantages
 Disadvantages
 Examples
 Tower Of Hanoi (TOH)

3. Introduction
 Method of defining function/procedure in
which the function being defined is
applied within its own.
 It is the function in which it will call itself
repeatedly until a certain condition is
satisfy.
 It is related to the last in first out nature
of the stack.
 Stack is the appropriate mechanism to
store the values of the parameter of
recursion.

4. Recursive Function
 A function that calls itself during its
execution.
 It repeats itself several times until it’s
end condition.

5. Advantages
 To write efficient programs using a
minimum amount of code.
 Nominal chance of syntax and logical
errors.
 Increases the program efficiency.

6. Disadvantages
 Can cause infinite loops and other
unexpected results if not written
properly.
 If the end condition is not defined then
the recursion will repeat forever,
causing the program to crash or hang
the entire computer system.

7. Examples
 Factorial function
 Fibonacci sequence
 Multiplication of natural numbers
 Binary search

8. Tower Of Hanoi (TOH)
 It can be solved by using recursion
technique.
 There exist three peg namely A, B & C.
 Several disks of different diameters are
placed in peg A.
 The large disk is always below the
smaller one.
 The objective is to move those disks to
peg C, using peg B as auxiliary.
 Only the top disk can be moved to other
peg.
 Only one disk may be moved at a time.

9. Algorithm (TOH)
To move n disks from A to C, using B as
auxiliary
 If n=1, move the single disk from A to C and
stop.
 Move the top n-1 disks from A to B, using C
as auxiliary.
 Move the remaining disk from A to C.
 Move the n-1 disks from B to C, using A as
auxiliary.

10. THE END
© Nalin Adhikari