calculations

[wayko]

is there a way to calculate an amount
on visual c++ ?
using a dialog box mfc(exe)

[no-one]

could you be more specific?

[wayko]

i want to subtract the current year 2001 from a year that a person inputs on a edit box.

i called the edit box IDC_YEAR and the the member variable is m_Year

i added the m_Age as a double
i want m_Age to represnt 2001

[no-one]

you need to make this part of the class to work as it is.

#include <stdlib.h>

void ClassNameHere::MakeCalcuation(void)
{
    char Buf[21];
    char* stopper;
    CWnd* Item = GetDlgItem(IDC_YEAR);
    Item.GetWindowText(Buf,20);
    m_Age =  2001 - strtod(buf,stopper);
}

[wayko]

this is my code i don't see where i am going wrong
the answer suppose to subtract m_Age which is set to 2001 and m_Year where the user insert the number. after they hit submit they should get a popup window that states you are x amount years old but i get you are 0.00 years old

// ageDlg.cpp : implementation file
//

#include "stdafx.h"
#include "age.h"
#include "ageDlg.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// CAgeDlg dialog

CAgeDlg::CAgeDlg(CWnd* pParent /*=NULL*/)
: CDialog(CAgeDlg::IDD, pParent)
{
//{{AFX_DATA_INIT(CAgeDlg)

m_Year = NULL;
//}}AFX_DATA_INIT
// Note that LoadIcon does not require a subsequent DestroyIcon in Win32
m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
//initialize m_Age field
m_Age = 2001;
}


void CAgeDlg:: DoDataExchange(CDataExchange* pDX)
{
CDialog:: DoDataExchange(pDX);
//{{AFX_DATA_MAP(CAgeDlg)
DDX_Control(pDX, IDC_SUBMIT, m_Submit);

DDX_Text(pDX, IDC_year, m_Year);
DDV_MaxChars(pDX, m_Year, 9999);
//}}AFX_DATA_MAP
}

BEGIN_MESSAGE_MAP(CAgeDlg, CDialog)
//{{AFX_MSG_MAP(CAgeDlg)
ON_WM_PAINT()
ON_WM_QUERYDRAGICON()
ON_EN_CHANGE(IDC_year, OnChangeyear)
ON_BN_CLICKED(IDC_SUBMIT, OnCancel)
ON_BN_CLICKED(IDC_Submit1, OnSubmit)
//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CAgeDlg message handlers

BOOL CAgeDlg::OnInitDialog()
{
CDialog::OnInitDialog();

// Set the icon for this dialog. The framework does this automatically
// when the application's main window is not a dialog
SetIcon(m_hIcon, TRUE); // Set big icon
SetIcon(m_hIcon, FALSE); // Set small icon

// TODO: Add extra initialization here

return TRUE; // return TRUE unless you set the focus to a control
}

// If you add a minimize button to your dialog, you will need the code below
// to draw the icon. For MFC applications using the document/view model,
// this is automatically done for you by the framework.

void CAgeDlg::OnPaint()
{
if (IsIconic())
{
CPaintDC dc(this); // device context for painting

SendMessage(WM_ICONERASEBKGND, (WPARAM) dc.GetSafeHdc(), 0);

// Center icon in client rectangle
int cxIcon = GetSystemMetrics(SM_CXICON);
int cyIcon = GetSystemMetrics(SM_CYICON);
CRect rect;
GetClientRect(&rect);
int x = (rect.Width() - cxIcon + 1) / 2;
int y = (rect.Height() - cyIcon + 1) / 2;

// Draw the icon
dc.DrawIcon(x, y, m_hIcon);
}
else
{
CDialog::OnPaint();
}
}

// The system calls this to obtain the cursor to display while the user drags
// the minimized window.
HCURSOR CAgeDlg::OnQueryDragIcon()
{
return (HCURSOR) m_hIcon;
}

void CAgeDlg::OnChangeyear()
{
// TODO: If this is a RICHEDIT control, the control will not
// send this notification unless you override the CDialog::OnInitDialog()
// function and call CRichEditCtrl().SetEventMask()
// with the ENM_CHANGE flag ORed into the mask.

// TODO: Add your control notification handler code here
}
void CAgeDlg::OnCancel()
{
// TODO: Add your control notification handler code here
CString s;
s.Format("You are %.2f years old", m_Age);
MessageBox(s, "Your age is...");

CDialog::OnCancel();
}

void CAgeDlg::OnSubmit()
{
// 1.
CalculateAge();
// 2.
CString s;
s.Format("You are %.2f years old", m_Age);

}
void CAgeDlg::CalculateAge()
{
if (m_Year < 2001)
{
m_Age -= m_Year;
}
}

[no-one]

change the OnSubmit() function to this

void CAgeDlg::OnSubmit() 
{ 
// 1. 
    char Buf[21];
    char* stopper;
// Get a pointer to the EditBox Control
    CWnd* Item = GetDlgItem(IDC_YEAR);
// Get its Text 20 characters max
    Item.GetWindowText(Buf,20);
// convert the string to a double
    m_Year =  strtod(buf,stopper);
    CalculateAge(); 
// 2. 
    CString s; 
    s.Format("You are %.2f years old", m_Age); 
}

[damyan]

or use the GetDlgItemInt to simplify your code

void CAgeDlg::OnSubmit() 
{ 
// 1. 
    m_Year =  GetDlgItemInt(IDC_YEAR);
    CalculateAge(); 
// 2. 
    CString s; 
    s.Format("You are %.2f years old", m_Age); 
}

[zen]

..or just call UpdateData() -

void CAgeDlg::OnSubmit() 
{ 
// 1. 
    UpdateData(TRUE);
    CalculateAge(); 
// 2. 
    CString s; 
    s.Format("You are %.2f years old", m_Age); 
}

[wayko]

it works
thanx for the help