ADDREV - Adding Reversed Numbers
Here's one way to reverse numbers without converting to strings and/or using std::reverse.  As per the challenge, this deals with only positive integers.

int RevNum( int num )
{
    int outVal = 0;
    while ( num &gt; 0 )
    {
        int temp = num % 10;
        outVal = ( outVal * 10 ) + temp;
        num /= 10;
    }
    return outVal;
}


Because the number starts and stays as a number, zeros are automatically handled properly.