//in your main form, this is how you instantiate your new class and access its members

  private: System::Void btnAdd_Click(System::Object^  sender, System::EventArgs^  e) 
            {
			        //---instantiate the DoMath class
                    DoMath^ myCalculator = gcnew DoMath();

                    //---assign values to the properties after making sure the data is double precision!
                    
                    double num1=0;
                    double num2 =0;


                    if(Double::TryParse(txtFirst->Text,num1) && Double::TryParse(txtSecond->Text, num2))
                        {
                 
                            myCalculator->FirstNumber =num1;
                            myCalculator->SecondNumber=num2;

                            double answer = myCalculator->AddThem();     //call the functions

                             txtResult->Text = answer.ToString();                //display the result
                         }
                    else
                         {
                         
                             MessageBox::Show("Please enter numbers only.", "System Message", MessageBoxButtons::OK, MessageBoxIcon::Error);
                            ClearForm();
                         }
            }















//_____________________________________________DoMath Class I add to the project
#pragma once

#include "Form1.h"          // make sure to reference the form where we will be calling this class from


using namespace System;
using namespace System::Windows::Forms;         // so we can use messagebox



//make sure the class is public. It is created as private by default!


public ref class DoMath sealed			//sealed means this class cannot be inherited and saves a bit of processing so use it!
{
public:

	DoMath(void)
	{
	}


        //---Create two fields for our properties

        static double _number1= 0;
        static double _number2 = 0;

        public: property double FirstNumber

            {
                double get()
                {
                    return _number1;
                }
            
                void set (double value)
                {
                    if(FirstNumber >=0)
                        _number1 = value;
                  
                }
            
            }

        public: property double SecondNumber
         {
                double get()
                {
                    return _number2;
                }
            
                void set (double value)
                {
                    if(SecondNumber >= 0)
                        _number2 = value;
                 
                }
            
            }


        public: double AddThem()
        {
             if (FirstNumber >= 0 && SecondNumber >= 0)
                {
                    return FirstNumber + SecondNumber;
                }

                            
        
        }