Example: Sum of Digits - String Conversion Method in C++

// Sum of Digits - String Conversion Method
#include <iostream>
#include <string> // Required for std::string and std::to_string
#include <numeric> // Required for std::accumulate (optional, for a more concise sum)
using namespace std;

int main() {
    int number;
    int sum = 0;
    
    // Step 1: Prompt user for input
    cout << "Enter an integer number: ";
    cin >> number;

    // Step 2: Convert integer to string
    // Handle negative numbers by converting to positive before string conversion
    string numStr;
    if (number < 0) {
        numStr = to_string(-number);
    } else {
        numStr = to_string(number);
    }

    // Step 3: Iterate through the string characters
    for (char digitChar : numStr) {
        // Convert char to int (e.g., '5' - '0' = 5)
        sum += (digitChar - '0'); 
    }

    // Step 4: Display the result
    cout << "The sum of the digits of " << number << " is: " << sum << endl;
    
    return 0;
}