Question

State any two differences between iteration and recursion.

Answer 1

Sr No.	Aspect	Iteration	Recursion
1.	Basic construct	Uses loop statements (for, while, do‑while). Control flow stays in a single function scope and state is updated via variables.	Uses a function that calls itself with smaller/simpler arguments until a base case is reached; each call has its own local state.
2.	Memory usage/overhead	Lower memory overhead: variables stay in one frame; no extra call‑stack frames are required (except normal function overhead).	Higher memory overhead: each recursive call pushes a new frame (locals/return address) on the call stack, which increases memory usage and can lead to stack overflow for deep recursion.
3.	Performance/runtime	Often faster in practice because it avoids repeated function call/return overhead and stack operations.	Often slower due to repeated function call overhead and stack management; some recursive solutions can be optimised (e.g., tail recursion), but not all languages optimise tail calls.
4.	Readability/expressiveness	Clear and concise for simple repetitive tasks; can become complex for problems naturally described by divide‑and‑conquer or tree structures.	Can be more concise and easier to reason about for problems that are naturally recursive (trees, divide‑and‑conquer, backtracking), making algorithms easier to express.
5.	When to prefer	Prefer when performance and low memory use matter, or when the problem is straightforward repetition (loops).	Prefer when the problem maps naturally to recursion (tree traversal, combinatorics, backtracking) or when a clearer, shorter implementation is important despite overhead.