while and do-while Loops

Repeating Code

int n = 1;
while (n <= 5) {
    cout << n << " ";
    n++;
}
// Output: 1 2 3 4 5

do-while — runs at least once

int x = 10;
do {
    cout << x;
    x++;
} while (x < 5);
// Output: 10  (ran once even though x > 5 already)

Extracting digits

int num = 12345, count = 0;
while (num > 0) {
    count++;
    num /= 10;   // removes last digit
}
// count == 5

Your Task

Write sumDigits(int n) that returns the sum of all digits of n.
Example: sumDigits(123) → 6 (1+2+3).
Hint: n % 10 gives the last digit, n / 10 removes it.