Reverse Number

#include <iostream>
#include <cmath>

auto reverseNumber(int num) -> int
{
    /*! Find total digits in num */
    int digit = static_cast<int>(log10(num));

    /*! Basic Condition */
    if(num == 0)
        return 0;

    return ((num % 10 * pow(10, digit)) + reverseNumber(num / 10));
}

int main()
{
   std::cout << reverseNumber(123);
}