A#1

#include "stdafx.h"
#include <iostream>
#define _USE_MATH_DEFINES
#include "math.h"
#include <windows.h>

using namespace std;

int fact(int n) {
    switch (n) {
    case 0: return 1;
    case 1: return 1;
    default: {
        int k = 1;
        for (int i = 1; i <= n; i++)
            k *= i;
        return k;
    }
    }
}

double receq(double t, double f, double x, double e, double k, int i) {
    double t1 = t * pow(-1, i + 1)* pow(x, 2) * (fact(2 *(i - 1))) * (2*i + x) / (fact(2 * i) * (2*(i-1) + x));
    f += t1;
    if (abs(f - k) < e) {
        return f;
    }
    else {
        return receq(t1, f, x, e, k, i + 1);
    }
}

void main()
{
    SetConsoleCP(1251);
    SetConsoleOutputCP(1251);
    double e;
    cout << "Введите точность вычисления" << endl;
    cin >> e;
    double x;
    cout << "Введите x" << endl;
    cin >> x;
    double k, t;
    k = sin(x) - cos(x) + 1;
    double r;
    r = receq(1, 0, x, e, k, 1);
    cout.precision(15);
    cout << "k = " << k << endl;
    cout.precision(15);
    cout << "r = " << r << endl;
    cin >> r;

}