//pendulum.h
#include<string>
using std::string;
#ifndef pendulum_H
#define pendulum_H

class Pendulum
{
public:
    Pendulum(const double,const double,double,double);
    //check function
    const double check(const double, const string) const;  //used for (L,M)
    // getfuncties
    double getL() const;
    double getM() const;
    double getTheta();
    double getOmega();
    //overload operator
    Pendulum operator+ (Pendulum);
    Pendulum operator*(const double a);
    Pendulum operator=(Pendulum);
    //copy constructor
    Pendulum(const Pendulum&  );
private:
    double L_,M_,Theta_,Omega_;
};
#endif

//pendulum.cpp
#include "pendulum.h"
#include <iostream>
#include <string>
using namespace::std;
//constructor
Pendulum::Pendulum(const double L, const double M, double Theta, double Omega)
         :L_(check(L,"L")),M_(check(M,"M"))
{}
//check functie
const double Pendulum::check(const double d, const string str) const
{
    if (d<0.)
    {
        cout << "ERROR: " << str << " (" << d << ") has to be positive"  << endl;
        exit(EXIT_FAILURE);
    }
    return d;
}
//getfuncties
double Pendulum::getM() const
{
    return M_;
}
double Pendulum::getL() const
{
    return L_;
}
double Pendulum::getTheta()
{
    return Theta_;
}
double Pendulum::getOmega()
{
    return Omega_;
}
//overloading operators
 Pendulum Pendulum::operator+ (Pendulum param)
{
return Pendulum(L_, M_, Theta_+param.Theta_, Omega_+param.Omega_);
}

Pendulum Pendulum::  operator* (const double param)
{
return Pendulum(L_, M_, param*Theta_, param*Omega_);
}

Pendulum Pendulum::operator=(Pendulum param)
{
return Pendulum(L_, M_, param.Theta_, param.Omega_);
}
//copy constructor
Pendulum::Pendulum(const Pendulum& Object)
{
*this=Object;
}

//doublependulum.h
#ifndef doublependulum_H
#define doublependulum_H
#include "pendulum.h"

class DoublePendulum
{
public:
    //constructor
    DoublePendulum(Pendulum ,Pendulum );
    //getfuncties
    Pendulum getUp();
    Pendulum getDown();
    //Overload operators
    DoublePendulum operator+ (DoublePendulum);
    DoublePendulum operator*(const double a);
    DoublePendulum &operator=(const DoublePendulum &);
    //copy constructor
    DoublePendulum(const DoublePendulum& );
private:
    Pendulum PendUp;
    Pendulum PendDown;
};
#endif


//doublependulum.cpp
#include "doublependulum.h"

//constructor
DoublePendulum::DoublePendulum(Pendulum Up,Pendulum Down)
               :PendUp(Up),PendDown(Down)
{}
//getfunctions
Pendulum DoublePendulum::getUp()
{
return PendUp;
}
Pendulum DoublePendulum::getDown()
{
return PendDown;
}
//Overload operators
DoublePendulum DoublePendulum::operator+ (DoublePendulum param)
{
return DoublePendulum(PendUp + param.PendUp,PendDown + param.PendDown);
}

DoublePendulum DoublePendulum::operator* (const double param)
{
return DoublePendulum(PendUp*param,PendDown*param);
}

DoublePendulum& DoublePendulum::operator= (const DoublePendulum& param)
{
return *this; // assign to members of this object
}
//Copy constructor
DoublePendulum::DoublePendulum(const DoublePendulum& Object)
{
*this=Object;
}


//Main.cpp
#include "pendulum.h"
#include "doublependulum.h"
int main()
{return 0;}