Мусор

OS_HW_1

#include <iostream>
#include <limits>
#include <cmath>
#include <fstream>

double calc(double a, double b, int n, double (*func)(double)) {
    double
        result = 0,
        h = (b - a) / n;

    for (int i = 0; i < n; ++i) {
        double dx = a + h / 2 + i * h;
        result += func(dx);
    }
    result *= h;

    return result;
}

int getIntinput(int max) {
    int input = 1;
    std::cin >> input;
    while (std::cin.fail() || input < 1 || input > max)
    {
        std::cin.clear();
        std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
        std::cout << "\ns\n";
        std::cin >> input;
    };
    return input;
}

double getDoubleInput() {
    double input = 0;
    std::cin >> input;
    while (std::cin.fail())
    {
        std::cin.clear();
        std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
        std::cin >> input;
    }
    return input;
}


int main() {
    const int count = 6;
    const char* strings[6]{ "sin(x)", "cos(x)", "tan(x)", "e^x", "ln(x)", "x^2" };
    double (*functions[count])(double) = { sin, cos, tan, exp, log, [](double x)->double {return x * x; } };

    std::cout << "Functions:\n  1. sin(x)\n  2. cos(x)\n  3. tg(x)\n  4. e^x\n  5. ln(x)\n  6. x^2\n";
    int func = getIntinput(count) - 1;
    std::cout << "Enter calculation bounds [a:b].\nEnter a:\n";
    double a = getDoubleInput();
    std::cout << "Enter b:\n";
    double b = getDoubleInput();
    double result = calc(a, b, 1000, functions[func]);
    std::cout << "\nResult: " << calc(a, b, 1000, functions[func]);

    std::ofstream myFile("result.txt");
    myFile << "Result: " << result << "\nFunction: " << strings[func] << "\nBounds: [" << a << " : " << b << "]"; 
    myFile.close();
    return 0;
}