Se desea calcular independientemente la suma de los números pares en impares comprendidos entre 50 y 400.

#include <iostream>
#include <iomanip>

int main()
{
   int sum_odd = 0, sum_even = 0;
   for (int i = 50; i <= 400; ++i) {
      if (i % 2 == 0) {
         sum_even += i;
      } else {
         sum_odd += i;
      }
   }
   std::cout << "Sum of even numbers between 50 and 400 is "
      << sum_even << std::endl;
   std::cout << "Sum of odd numbers between 50 and 400 is "
      << sum_odd << std::endl;
   return 0;
}