/* (c) KreatoR '97
	program that calculates e using:
	e=1+1/1!+1/2!+1/3!+...+1/i!+...
*/

#include <stdio.h>
#ifndef M_E
	#include <math.h> //here comes shit if one forgets ;) i did.
#endif
#ifndef BLINK
	#include <conio.h>
#endif

long float fakto(long float); //prototype function

void main() //start sub main
{
	long int i;
	int n,p=1;
	double sum;

	clrscr();
	printf("Unesi do kojeg 'n' da se racuna e ");
	scanf("%d",&n);
	for (i=0,sum=0;i<=n;i++) {sum+=p/fakto(i);p=-p;}
	sum=1/sum;
	printf("Stvarni 'e' je %f\n",M_E);
	printf("Izracunan je %f\n",sum);
	printf("Apsolutna pogreska je %f\n",fabs(M_E-sum));
	getch();
}


//function facto
long float fakto(long float racun)
{
	if (racun>2) {racun*=fakto(racun-1);}
		else if (!racun) {racun=1;}
	return(racun);
}