Dokolkoto widqh e shodqsht reda taka che mai towa wurshi rabota .. :)
Sa koito razbira ot matematika da ne se smee mnogo .. :)
Da me izwinish ama sam go pisal na C, neshto ne si spomnqm pascal-a ... :)

#include <stdio.h>

#include <stdlib.h>

#include <math.h>



#define EPS 1.0e-10



void main(int argc, char *argv[]) {

  double x    =  0.0;

  double sum1 =  0.0;

  double sum2 =  0.0;

  double xN   =  1.0;

  double oneN =  1.0;

  int n = 1;



  if(argc < 2) {

	  printf("Usage: rowsum <number>\n");

	  return;

  }



  x = atof(argv[1]);

  while(1) {

	  xN *= x;

	  sum2 += (oneN*xN)/(float)n;

	  if(abs(sum2 - sum1) < EPS ) {

		  break;

	  }

	  sum1 = sum2;

	  oneN *= -1;

	  n++;

  }



  printf("Sum is: %.20f", sum2);

}