#include <iostream>
#include <cassert>
#include <fstream>
#include <cmath>

using namespace std;

#define M_PI 3.1415926

class Evaluate {

    protected:
        double formula;
    public:
        virtual void set() = 0;
        virtual void get() = 0;
        virtual double calc() = 0;
        virtual void getResult() = 0;
};

class Force : public Evaluate {
    private:
        double k, T, R, F;

        void checkParams() {
            assert(k > 0 && T > 0 && R > 0 && F > 0 &&
                   T >= 1000 && T <= 1500 && R >= 900 && R <= 1700 &&
                   F >= 140 && F <= 300);
        }

    public:
        Force() {
            k = 0, T = 0, R = 0, F = 0;
        }

        Force(double _k, double _T, double _R, double _F) :k(_k), T(_T), R(_R), F(_F) {}
        Force(const Force& x) {
            k = x.k;
            T = x.T;
            R = x.R;
            F = x.F;

        }
        void set() {
            cout << "Enter information about: " << endl;

            cout << "k = ";
            cin >> k;
            cout << endl;
            cout << "T = ";
            cin >> T;
            cout << endl;
            cout << "R = ";
            cin >> R;
            cout << endl;
            cout << "△F = ";
            cin >> F;

            cout << endl << endl;
        }
        void get() {
            cout << "Information about" << endl;
            cout << "k = " << k;
            cout << endl;
            cout << "T = " << T;
            cout << endl;
            cout << "R = " << R;
            cout << endl;
            cout << "△F = " << F;
            cout << endl << endl;
        }
        double calc() {

            formula = sqrt(4*k*T*R*F);
            return formula;
        }
        void getResult() {
            cout << "Evaluated object: " << formula << endl;
        }
        Force& operator = (const Force& x) {

            k = x.k;
            T = x.T;
            R = x.R;
            F = x.F;

            return *this;
        }

        bool operator == (const Force& x) {
            return formula == x.formula;
        }
        bool operator != (const Force& x) {
            return formula != x.formula;
        }
        bool operator > (const Force& x) {
            return formula > x.formula;
        }
        bool operator < (const Force& x) {
            return formula < x.formula;
        }
        bool operator >= (const Force& x) {
            return formula >= x.formula;
        }
        bool operator <= (const Force& x) {
            return formula <= x.formula;
        }

        friend ifstream& operator >> (ifstream& ifs, Force& x);
        friend ofstream& operator << (ofstream& ofs, Force& x);
        friend istream& operator >> (istream& is, Force& x);
        friend ostream& operator << (ostream& os, Force& x);
        friend void tabulate(Force data, double dR, double R0, double R1, ofstream& ofs);
};

ifstream& operator >> (ifstream& ifs, Force& x) {
    ifs >> x.k >> x.T >> x.R >> x.F;
    return ifs;
}

ofstream& operator << (ofstream& ofs, Force& x) {
    ofs << "Information about:" << endl;
    ofs << "k = " << x.k;
    ofs << endl;
    ofs << "T = " << x.T;
    ofs << endl;
    ofs << "R = " << x.R;
    ofs << endl;
    ofs << "△F = " << x.F;
    ofs << endl << endl;
    return ofs;
}

istream& operator >> (istream& is, Force& x) {

    cout << "Information about: " << endl;
    cout << "k = ";
    is >> x.k;
    cout << endl;
    cout << "T = ";
    is >> x.T;
    cout << endl;
    cout << "R = ";
    is >> x.R;
    cout << endl;
    cout << "△F = ";
    is >> x.F;
    cout << endl << endl;
    return is;
}

ostream& operator << (ostream& os, Force& x) {
    os << "Information about:" << endl;
    os << "k = " << x.k << endl;
    os << "T = " << x.T << endl;
    os << "R = " << x.R << endl;
    os << "△F = " << x.F << endl << endl;
    return os;
}

void tabulate(Force data, double dR, double R0, double R1, ofstream& ofs) {
    double R = R0;
    int n = ((R1 - R0) / dR) + 1, i = 0; // кількість точок
    double x[n], y[n];

    cout.precision(3);
    cout << scientific;

    ofs.precision(3);
    ofs << scientific;

    do {
        x[i] = R;

        data.R = R;
        data.calc();

        y[i] = data.calc();

        R += dR;

        cout << "R = " << x[i] << endl << "E = " << y[i] << endl << endl;
        ofs << "R = " << x[i] << endl << "E = " << y[i] << endl << endl;

        i++;
    } while (R <= (R1 + 1e-7)); // умова виходу із табулювання
}

int main() {

    cout << "TEST BY CONSTRUCTORS" << endl;
    Force x;
    cout << "Default constructor:" << endl << x;
    Force y(1.37, 1000./1500, 900./1700, 140./300);
    double yRes = y.calc();
    cout << "Init constructor:" << endl << y;
    Force z = y;
    cout << "Copy constructor:" << endl << z;

    cout << "Operator ==" << endl;
    cout << "Output: " << boolalpha << (x == y) << endl << endl;

    cout << "Operator !=" << endl;
    cout << "Output: " << boolalpha << (x != y) << endl << endl;

    cout << "Operator < " << endl;
    cout << "Output: " << boolalpha << (x < y) << endl << endl;

    cout << "Operator <=" << endl;
    cout << "Output: " << boolalpha << (x <= y) << endl << endl;

    cout << "Operator >" << endl;
    cout << "Output: " << boolalpha << (x > y) << endl << endl;

    cout << "Operator >=" << endl;
    cout << "Output: " << boolalpha << (x >= y) << endl << endl;

    cout << "Operator =" << endl;
    x = y;
    cout << "X object:" << endl;
    x.get();
    cout << "Y object:" << endl;
    y.get();


    cout << endl << endl << "TEST BY OPERATORS" << endl << endl;
    cout << "X object:" << endl;
    x.get();
    cout << "Y object:" << endl;
    y.get();


    cout << endl << endl << "TEST BY FUNCTIONS" << endl << endl;
    cout << "Set function:" << endl;
    x.set();
    cout << "Get function:" << endl;
    x.get();
    x.calc();
    cout << "Result function:" << endl;
    x.getResult();

    Force a;
    ifstream ifs("inout.txt");
    ofstream ofs("output.txt");

    ifs >> a;
    double aRes = a.calc();

    cout << a << aRes;
    ofs << a << aRes;

    return 0;
}