Sum of Digits of a Number?

Short answer: int SumOfDigits(int n) { int sum = 0; n = Math.Abs(n); while (n > 0) { sum += n % 10; n /= 10; } return sum; } Explanation: Extract digits using modulo 10 and add.

Example code

int SumOfDigits(int n)
{
int sum = 0;
n = Math.Abs(n); while (n > 0) {
sum += n % 10;
n /= 10;
}
return sum;
} Explanation: Extract digits using modulo 10 and add.

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.