#include <iostream>
#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;
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);
};

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;
}

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;
}