Glossary
Base Case
The condition within a recursive method that stops the recursion, preventing an infinite loop and providing a direct, non-recursive solution for the smallest subproblem.
Example:
In a recursive method to calculate the sum of numbers from 1 to n, the base case would be when n is 0, returning 0 directly without further calls.
Call Stack
A data structure that stores information about the active subroutines of a computer program, including the state and local variables of each recursive call, managing their execution order.
Example:
When tracing a deep recursive function, visualizing the call stack helps understand how each function call is added and removed, and how return values propagate back up.
Iteration
A programming approach that uses loops (like `for` or `while`) to repeatedly execute a block of code until a condition is met, as an alternative to recursion.
Example:
Calculating the sum of elements in an array using a for loop is a common example of iteration, performing a task repeatedly without self-calling methods.
Recursion
A programming technique where a method solves a problem by calling itself repeatedly with smaller subproblems until a base case is reached.
Example:
Calculating the factorial of a number, like 5!, can be elegantly solved using recursion, where 5! is defined as 5 * 4!, and so on, until 1! is reached.
Recursive Algorithms
Algorithms designed to solve problems by breaking them down into smaller instances of the same problem, often implemented using recursive methods.
Example:
Quicksort and Mergesort are classic examples of efficient recursive algorithms used for sorting large datasets by dividing them into smaller, sortable parts.
Recursive Call
The statement within a recursive method where the method invokes itself, typically with modified parameters to move closer to the base case.
Example:
In a fibonacci(n) method, the line return fibonacci(n - 1) + fibonacci(n - 2); contains the recursive call that drives the sequence generation.
Recursive Method
A method that calls itself directly or indirectly to solve a problem, breaking it down into smaller, similar subproblems.
Example:
A countdown recursive method might print a number and then call itself with number - 1 until it reaches zero, demonstrating a self-referential process.