IT1815 Recursion Types

Questions and Answers

What is recursion?

A process where a function calls itself once or multiple times to solve a problem.

Which type of recursion calls itself only once each time it is invoked?

Mutual recursion

Linear recursion (correct)

Binary recursion

Indirect recursion

What can lead to infinite recursion?

Using iteration

Changing the state correctly

A base case that is never reached (correct)

Correct recursive calls

Recursive calls require more memory than iterative loops.

True Signup and view all the answers

What is the main difference between recursion and iteration?

Recursion terminates when a base case is reached, while iteration terminates when a condition is false. Signup and view all the answers

What is an example of binary recursion?

Calculating Fibonacci series Signup and view all the answers

What is mutual recursion?

A function that calls another function, which eventually calls the original Signup and view all the answers

Study Notes

Recursion Fundamentals

Recursion involves a function calling itself either directly or indirectly to solve problems.
Direct recursion: A method calls itself directly.
Indirect recursion: A method invokes another method, which eventually calls the original method.
Infinite recursion occurs when a recursive function lacks a stopping condition.

Requirements for Recursive Algorithms

Must have a base case that halts the recursion process.
State must change towards reaching the base case, modifying some data used by the algorithm.
The function must call itself recursively.

Types of Recursion

Linear Recursion: The function calls itself once per invocation. Example: Finding the factorial of a number.
Tail Recursion: The recursive call is the last operation in the function. Example: Finding the greatest common divisor of two non-zero integers.
Binary Recursion: The function calls itself twice during its execution. Example: Fibonacci series computation.
Mutual Recursion: Functions call each other in pairs or groups. Example: Determining if an integer is even or odd.

Recursion vs. Iteration

Recursion:
- Terminates upon reaching a base case.
- Requires additional memory for each recursive call, which may lead to stack overflow if infinite.
- Recursive solutions are often more intuitive and simpler to formulate for certain problems.
Iteration:
- Ends when a specific condition is false.
- Does not consume extra memory for each iteration, which can lead to infinite loops.
- Iterative solutions may not always be as straightforward as their recursive counterparts.

Description

This quiz covers the fundamentals of recursion, specifically focusing on types such as linear recursion. You'll explore how functions invoke themselves, using examples like factorial calculation. Enhance your understanding of recursive processes in programming.