C++ for statement Multiple initializations in a loop expression

#include <iostream>
#include <iomanip>
int main()//w  ww .j  a v  a  2 s  .co  m
{
  unsigned int limit {};
  std::cout << "This program calculates n! and the sum of the integers"
            << " up to n for values 1 to limit.\n";
  std::cout << "What upper limit for n would you like? ";
  std::cin >> limit;

  // Output column headings
  std::cout << std::setw(8) << "integer" << std::setw(8) << " sum"
                            << std::setw(20) << " factorial" << std::endl;

  for (unsigned long long n {1ULL}, sum {}, factorial {1ULL} ; n <= limit ; ++n)
  {
    sum += n;                          // Accumulate sum to current n
    factorial *= n;                    // Calculate n! for current n
    std::cout << std::setw(8) << n << std::setw(8) << sum
              << std::setw(20) << factorial << std::endl;
  }
}