#include"stdafx.h"
#include<conio.h>
#include<vector>
#include<clocale>
#include<iostream>
#include<math.h>
using namespace std;
double f(double x, double eps)
{
#define pi 3,1415926
    double sum = (pi / 2);
    long n = 1;
    double fn = 1 / (3 * pow(x, 3.00));
    while (eps < fabs(fn))
    {
        sum += fn;
        n += 1;
        fn *= pow(-1, n + 1);
        fn /= (2 * n + 1) * pow(x, 2 * n + 1);
    }
    return sum;
}
int main()
{
    char sign[] = " ";
    double x, fx, dx = 0.1, xn = 0, xk = 0, eps = 0.001;

    cout << "Enter xn : ";
    cin >> xn;
    printf("Enter xk : ");
    cin >> xk;
    printf("|----------------|\n");
    printf("|    x   |  atan |\n");
    printf("|----------------|\n");
    for (x = xn; x <= xk; x += dx)
    {
        fx = f(x, eps);
        if (x < 3)
            sign[0] = '\0';
        else
            sign[0] = ' ';
        printf("|%s%.4f|%s%.4f  |\n",
            sign, x, sign, atan(fx));
    }
    printf("|---------------|\n");
    system("pause");
    return 0;
}