ParProg4.7

#define _USE_MATH_DEFINES
#include <Windows.h>
#include <iostream>
#include <string>
#include <omp.h>
using namespace std;

double f(double x)
{
    return 1 / (1 + x * x);
}

int main() {
    setlocale(LC_ALL, "Russian");

    int N = 1e8;

    double a = 0, b = 1e6, h = (b - a) / 2 / N;

    double sum1 = 0;

#pragma omp parallel for reduction(+:sum1)
    for (int k = 1; k < 2 * N; k += 2)
        sum1 += f(a + k * h);

    double sum2 = 0;

#pragma omp parallel for reduction(+:sum2)
    for (int k = 2; k < 2 * N; k += 2)
        sum2 += f(a + k * h);

    double res = h / 3 * (f(a) + f(b) + (4 * sum1) + (2 * sum2));

    cout << "Реальный ответ: " << M_PI / 2 << "\n";
    cout << "Ответ, полученный алгоритмом: " << res;

    return 0;
}