/*  C  */

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

#define N 100000000


int main () {
   float f = 0;
   for (int i = 1; i <= N; i++) {
      f = f + 1.0 / i;
   }
   printf("sum from 1 to %d is %f\n", N, f);
   // sum from 1 to 100000000 is 15.403683

   f = 0;
   for (int i = N; i > 1; i--) {
      f = f + 1.0 / i;
   }
   printf("sum from %d to 1 is %f\n", N, f);
   // sum from 100000000 to 1 is 17.807919
}