Kindly need help for this code explaination

// Write clean code, it makes more sense.
void main ()
{
    int digit;                                    // create a new variables
    for (digit = 0; digit <= 9 ; digit++) {       // run the loop using "digit" variable
                                                  // until digit becomes 10
        cout << digit << "\n";                    // print current digit, each time
    }

    digit= 5 * digit;                             // Multiply last value of digit (10)
                                                  // with 5
    --digit;                                      // Decrease its value by 1 (--)
    cout << digit;                                  // Print it.
}