What is the difference between recursion and…

Recursion is when a function calls itself. Iteration is the repeated execution of a block of code using loops.

Main differences:

Mechanism: Recursion uses a call stack. Iteration uses loop constructs (for, while).
Flow control: Recursion branches inward. Iteration is sequential.
Base case: Recursion has a base case. Iteration has a loop termination condition.
Memory: Recursion can consume more memory due to the call stack. Iteration is more memory-efficient for many repetitions.
Readability: For some tasks (like tree traversal), recursion can be more readable. For simple repetitions, iteration is often clearer.
Performance: Iteration is usually faster due to the absence of function call overhead.

Example in Python:

Calculating factorial recursively:

# Recursive function to calculate factorial
def factorial_recursive(n):
    if n == 0:  # Base case
        return 1
    else:
        return n * factorial_recursive(n-1)

Calculating factorial iteratively:

# Iterative function to calculate factorial
def factorial_iterative(n):
    result = 1
    for i in range(1, n + 1):
        result *= i
    return result

Choosing between recursion and iteration depends on the specific task, performance and memory requirements, as well as coding style preferences. Recursion is often used for problems with recursive data structures (trees, graphs), while iteration is versatile for repeating sequential actions. Python has a recursion depth limit, which can be a factor when processing large data.

What is the difference between recursion and iteration?