Example: Sum of Individual Digits of a Positive Integer in C++

// Sum of Individual Digits of a Positive Integer
#include <iostream>
using namespace std;

int main() {
    int number;
    int sum = 0;
    int digit;

    // Step 1: Prompt user for input
    cout << "Enter a positive integer: ";
    cin >> number;

    // Step 2: Handle non-positive input (optional but good practice)
    if (number < 0) {
        cout << "Please enter a positive integer." << endl;
        return 1; // Indicate an error
    }

    // Step 3: Iterate to sum digits
    int originalNumber = number; // Store original for output message

    // Loop continues as long as 'number' is greater than 0
    while (number > 0) {
        // Extract the last digit using the modulo operator
        digit = number % 10;
        
        // Add the extracted digit to the sum
        sum += digit;
        
        // Remove the last digit from the number using integer division
        number /= 10;
    }

    // Step 4: Display the result
    cout << "The sum of digits of " << originalNumber << " is: " << sum << endl;

    return 0;
}