#include "stdafx.h"
#include <stdio.h>
#include <math.h>
 
#define f(x) 1/(1+x)
double simpson(double a, double b, double eps)
{
    double h, s, s1, s2, s3;
    double x;
    s2 = 1;
    h = b-a;
    s = f(a)+f(b);
    do
    {
        s3 = s2;
        h = h/2;
        s1 = 0;
        x = a+h;
        do
        {
            s1 = s1+2*f(x);
            x = x+2*h;
        }
        while(x<b);
        s = s+s1;
        s2 = (s+s1)*h/3;
        x = fabs(s3-s2)/15;
    }
    while(x>eps);
    return s2;
}
 
void main()
{
	printf("%.4f",simpson(0.,1.,0.001));
}