#include <stdio.h>
#include <stdlib.h>

int main(void)
{
   unsigned long Isum = 0, Qsum = 0;
   int buffer[1024];
   size_t i;
   /*
    * Fill the buffer with values between -100 and 100
    * (you can probably skip this).
    */
   srand(time(NULL));
   for ( i = 0; i < sizeof buffer / sizeof *buffer; ++i )
   {
      buffer[i] = rand() % 200 - 100;
   }
   /*
    * Calculate sums.
    */
   for ( i = 0; i < sizeof buffer / sizeof *buffer; ++i )
   {
      if ( i % 2 )  /* odd */
      {
         Qsum += abs(buffer[i]);
      }
      else          /* even */
      {
         Isum += abs(buffer[i]);
      }
   }
   printf("Isum = %lu, Qsum = %lu\n", Isum, Qsum);
   return 0;
}

/* my output
Isum = 26194, Qsum = 24823
*/