Tutorial 10 Q1 with added exception handling

//pasterbin.com/u/thewhitefang
// Tutorial 10 Q1 with added exception handling
#include<iostream>
#include<string>

using namespace std;

class Data{

public:
    double m_Opposite;
    double m_Adjacent;
    double m_Hypotenuse;

};

//interface class - pure virtual class (contains pure virtual functions)
//arrow means association
class ITrigo{

public:
    virtual void CompAngle(Data input, double& angle1, double& angle2) = 0; //add 'virtual' and '=0'
};

//arrow means realization of prv class

class SinCsc:public ITrigo{ //worker class realizing Itrigo
public:
    void CompAngle(Data input, double& angle1, double& angle2)
    {
        angle1 = input.m_Opposite / input.m_Hypotenuse; //sin
        angle2 = input.m_Hypotenuse / input.m_Opposite;
    }

};

class TanCot : public ITrigo{

    void CompAngle(Data input, double& angle1, double& angle2)
    {
        angle1 = input.m_Opposite / input.m_Adjacent; //sin
        angle2 = input.m_Opposite / input.m_Hypotenuse;
    }


};

//black diamond represents composition - strong association
//white diamond means aggregation - lightly associated
//no dotted line so no inheritance

class Trigo
{
private:
    Data m_input;
    ITrigo* m_pObject;

public:
    Trigo(){

    m_pObject = NULL;

    }
    void SetAttributes(Data input)
    {
        m_input = input;
    }
    void SetTrigoObject(ITrigo* pObject)
    {
        m_pObject = pObject;
    }
    void Compute(double& angle1, double& angle2)
    {
        //to access member variable/function of other class
        if(m_pObject == NULL)
        {
            throw string("Error: m_pObject is not initialized");
        }
        m_pObject->CompAngle(m_input, angle1, angle2);
    }

};

int main(){

    Data d;
    Trigo t;

    d.m_Opposite = 4.0; d.m_Adjacent = 3.0; d.m_Hypotenuse = 5.0;
    t.SetAttributes(d);
    //iv

    ITrigo *pObj = new SinCsc(); //Itrigo takes the form of SInCsc
    //t.SetTrigoObject(pObj); //if not called program will crash

    double sine, cosecant;
    try
    {
        t.Compute(sine, cosecant);
        cout << "Sine: " << sine << endl;
        cout << "Cosecant: " << cosecant << endl;
    }

    catch(string obj)
    {
        cout << obj << endl;
    }



    delete pObj;
    //new code
    pObj = new TanCot();
    t.SetTrigoObject(pObj); // to set new values

    double tangent, cotangent;
    t.Compute(tangent, cotangent);

    cout << "Tangent: " << tangent << endl;
    cout << "Cotangent: " << cotangent << endl;

    delete pObj;

    return 0;
}