20181001_1

#include <iostream>
#include <cmath>

int main() {
    double epsilon, x;
    std::cout << "Enter epsilon: ";
    std::cin >> epsilon;
    std::cout << "Enter X: ";
    std::cin >> x;
    double accurate = sin(x);

    double prev = x;
    int iteration = 0;
    while (true) {
        iteration++;
        double v = prev * (1 - pow(x,2)/(pow(M_PI, 2)*pow(iteration, 2)));
        double delta = fabs(v - prev);
        std::cout << "Current iteration: " << iteration << std::endl;
        std::cout << "Current delta: " << delta << std::endl;
        if (delta < epsilon) {
            prev = v;
            break;
        }
        prev = v;
    }
    std::cout << "Iterations: " << iteration << std::endl;
    std::cout << "Accurate value: " << accurate << std::endl;
    std::cout << "Not accurate value: " << prev << std::endl;
    return 0;
}