Swap two numbers without using a temporary variable?

Short answer: public void Swap(ref int a, ref int b) { if (a != b) { a ^= b; b ^= a; a ^= b; } } Explanation: XOR swap algorithm exchanges values without extra storage. (Check a != b to avoid zeroing when both are same.)

Example code

public void Swap(ref int a, ref int b) {
if (a != b) {
a ^= b;
b ^= a;
a ^= b;
}
} Explanation: XOR swap algorithm exchanges values without extra storage. (Check a != b to avoid zeroing when both are same.)

Real-world example (ShopNest)

In coding rounds, state complexity aloud, write a clear ShopNest-flavored example (orders, carts), then handle edge cases (empty list, null, overflow).

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.