C++ Exercises: Add two binary numbers

#include <iostream> // Including input-output stream header file
#include <math.h>   // Including math functions header file
using namespace std; // Using the standard namespace

int main() { // Start of the main function
    long bn1, bn2; // Declaration of variables to store binary numbers
    int i = 0, r = 0; // Initializing variables for iteration and remainder
    int sum[20]; // Array to store the sum of binary digits

    cout << "\n\n Addition of two binary numbers:\n"; // Displaying the purpose of the program
    cout << "-----------------------------------\n";
    cout << " Input the 1st binary number: ";
    cin >> bn1; // Taking input for the first binary number
    cout << " Input the 2nd binary number: ";
    cin >> bn2; // Taking input for the second binary number

    // Loop to add binary digits
    while (bn1 != 0 || bn2 != 0) {
        // Adding binary digits and remainder, storing the sum
        sum[i++] = (int)((bn1 % 10 + bn2 % 10 + r) % 2);
        r = (int)((bn1 % 10 + bn2 % 10 + r) / 2);
        bn1 = bn1 / 10; // Moving to the next digit in the first binary number
        bn2 = bn2 / 10; // Moving to the next digit in the second binary number
    }

    if (r != 0) { // Checking if there's a remaining carry
        sum[i++] = r; // Adding the remaining carry to the sum
    }

    --i; // Decrementing the index to reach the end of the sum array

    cout << " The sum of two binary numbers is: ";
    while (i >= 0) { // Loop to print the sum of binary numbers
        cout << (sum[i--]); // Printing each digit of the sum
    }
    cout << ("\n");  
    return 0; // Returning 0 to indicate successful program execution
}