Beginner · digit peeling

Digit Sum

Sum the digits of an integer: 1234 → 1+2+3+4 = 10. Same peel loop as Count the Digits, but accumulating this time.

Problem

Input: one integer n (−10⁹ ≤ n ≤ 10⁹).

Output: the sum of its digits (the minus sign doesn't count).

Sample:

Input	Output
`1234`	`10`
`-305`	`8`

Program.cs — your solution

Custom input for "Run my input"

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Hint 1 — peel and add

Each pass: sum += n % 10; takes the last digit, n = n / 10; drops it. Loop until zero.

Hint 2 — the traps

Negative input loops forever with n > 0 — take Math.Abs(n) first. And n = 0 should print 0 (do-while handles it for free).

Solution (try first!)

int n = Math.Abs(int.Parse(Console.ReadLine()));
int sum = 0;
do { sum += n % 10; n = n / 10; } while (n > 0);
Console.WriteLine(sum);

Same loop, different fold — count became sum. That's the accumulator pattern from Lesson 4 doing its job. Next: Leap Year.