The document provides instructions for adding functionality to a calculator application. It instructs the developer to add two integer variables to store the edit field and result values. It also provides code to initialize these variables and add event handler functions for buttons to multiply and add to the edit field, add the edit field to the result, and clear the edit field. The handlers implement this functionality by manipulating the two integer variables.

1. Calculator

16. Add variable to edit ctrl

18. Add variable to CCalculatorDlg.h
…………………
public:
int m_edit;
int m_res;
};

19. Initialize declared var in CCalculatorDlg::OnInitDialog() from
CalculatorDlg.cpp
…………………………………….
// TODO: Add extra initialization here
m_res = 0;
m_edit = 0;
return TRUE; // return TRUE unless you set the focus to a control
}
………………..

20. • Add handler to IDC_BUTTON1

24. void CCalculatorDlg::OnClickedButton1()
{
// TODO: Add your control notification handler code here
m_edit = m_edit * 10 + 1;
UpdateData(FALSE);
}

25. Add handler to IDC_BUTTON2

29. void CCalculatorDlg::OnClickedButton2()
{
// TODO: Add your control notification handler code here
m_res = m_res + m_edit;
m_edit = 0;
}

30. Add handler to IDC_BUTTON3:

34. Add handler to IDC_BUTTON4:

38. void CCalculatorDlg::OnClickedButton4()
{
// TODO: Add your control notification handler code here
m_edit = m_edit + m_res;
UpdateData(FALSE);
}