C / C++ / MFC

Re: question about classes without data

7-Jan-06 22:31

He needs it not me.

-Prakash

vikas amin7-Jan-06 23:02

vikas amin

7-Jan-06 23:02

Ok prakash

Vikas Amin
Embin Technology
Bombay
vikas.amin@embin.com

Re: question about classes without data

Prakash Nadar7-Jan-06 22:32

BFFM_SETSELECTION question

7-Jan-06 22:32

http://www.janiry.com/bruce-eckel/[^]

-Prakash

nm_1147-Jan-06 19:51

7-Jan-06 19:51

The MSDN docs say "The path can be specified as a Unicode string or a PIDL" for the BFFM_SETSELECTION message (inside a BrowseCallbackProc function after calling SHBrowseForFolder), but when I send a Unicode string instead of an ansi one it fails. Is the documentation wrong?

Prakash Nadar7-Jan-06 21:16

7-Jan-06 21:16

Did you set the wParam as true?

-Prakash

nm_1148-Jan-06 6:28

8-Jan-06 6:28

yep, it works fine with an ansi string.

Prakash Nadar8-Jan-06 14:58

8-Jan-06 14:58

How are you sending the unicode string ? can you dump the section of code ?

-Prakash

nm_1148-Jan-06 17:01

8-Jan-06 17:01

if you uncomment the commented out lines it works fine in unicode builds but not ansi. it's being converted to unicode ok because OutputDebugStringW prints what it's supposed to.

int CALLBACK BrowseCallbackProc_SetInitFolder(HWND hWnd, UINT uMsg, LPARAM lParam, LPARAM lpData)
{
	if (uMsg == BFFM_INITIALIZED)
	{
//#ifdef UNICODE
		SendMessage(hWnd, BFFM_SETSELECTION, TRUE, lpData);
//#else
//		WCHAR sz[MAX_PATH];
//		MultiByteToWideChar(CP_ACP, 0, (LPTSTR)lpData, -1, sz, MAX_PATH);
//		OutputDebugStringW(sz);
//		SendMessage(hWnd, BFFM_SETSELECTION, TRUE, (LPARAM)sz);
//#endif
	}
	return 0;
}

Prakash Nadar8-Jan-06 17:36

8-Jan-06 17:36

In Ansi build you should NOT convert the string to Unicode while using windows APIs,

Check this link[^] and search for BFFM_SETSELECTION

The Microsoft documentation has a couple of minor errors I should point out in case you try to program SHBrowseForFolder in C. The documentation says to pass the string for BFFM_SETOKTEXT in WPARAM; actually, it's LPARAM. It also says that BFFM_SETSELECTION requires a Unicode string, but BFFM_SETSELECTION is available in both A and W flavors, so you can use LPCTSTR.

-Prakash

-- modified at 23:38 Sunday 8th January, 2006

nm_1148-Jan-06 18:40

Re: questions about pointers

8-Jan-06 18:40

Mr.Prakash wrote:
The Microsoft documentation has a couple of minor errors

ah, thats what i thought. thanks.

questions about pointers

neodeaths7-Jan-06 19:28

neodeaths

7-Jan-06 19:28

i was just wondering if this is possible?:

i have 2 class
and each of them i declared 10 object and 1 pointer:

grahpic_card gc[10],*ptr_gc;
mother_board mb[10],*ptr_mb;

is there a way i can store any one of the pointer in 1 pointer something like this

???? *ptr1;

instead of having to use 1 pointer for each of the class i would like to use 1 pointer for BOTH of the class is that possible if so please teach me how

Prakash Nadar7-Jan-06 20:58

Re: questions about pointers

7-Jan-06 20:58

You need some understanding of C++.

use a baseclass from which graphic_card and mother_board will be derived from.

for example

class Mother_board :public Base
and
class Graphic_card :public Base

Then
Base *base;
Mother_board *mBoard;
Graphic_card *gCard;

<<<assumeing that="" the="" mboard="" and="" gcard="" are="" initialed.="">>>

then

base = mBoard or <<< you can use reinterpret_cast too >>>
base = gCard is valid assignmnet.

add virtual or pure virtual methods in both base and derived class so that you can call the methods as base->foo();

-Prakash

vikas amin7-Jan-06 21:52

vikas amin

7-Jan-06 21:52

reinterprit_cast
is the key word
Cool | :cool:

but its not that simple
as u feel as c++ doesnot
like such type casting and
might lead u some error in
programe if reiterprit is not
used with proper cution .

Vikas Amin
Embin Technology
Bombay
vikas.amin@embin.com

Re: questions about pointers

Prakash Nadar7-Jan-06 22:01

Why the application could not run at Windows XP?

7-Jan-06 22:01

dynamic_cast can be used for better safety.

-Prakash

rushing7-Jan-06 17:22

rushing

7-Jan-06 17:22

The applicaiton is ok in Windows 2000.
When run in Windows Xp ,at the beginning there is a error which said the memory could not be visited.
I link WS2_32.LIB in the project.
Why?
Thanks!

Re: Why the application could not run at Windows XP?

Prakash Nadar7-Jan-06 21:44

GDI+ Visual C++ wrapper class operators missing?

7-Jan-06 21:44

rushing wrote:
The applicaiton is ok in Windows 2000.

Is it your application?
Is it memory exeception? if it is written by you can u identify the code from where the memory exception is raised?

-Prakash

bob169727-Jan-06 15:03

bob16972

7-Jan-06 15:03

I just realized the Point class does not provide the = operator. Now that I'm trying to actually use GDI+ in my apps, I'm finding the classes for Rect, RectF, Point, and PointF to be rather peculiar in design.

Also, Rect doesn't provide functions that return the endpoints.

I can't create an Array of Point and copy another Point into one of it's elements (unless it's during initialization). Instead, I have to resort to assigning the X and Y members explicitly into each array element.

I'm not sure if there is some bigger picture I'm missing here or some new highly ultra OOP paradigm I missed the whitepaper on or if this design is just weak and missing some of the useful operators that MFC provided on many of it's classes.

Does anyone have any insight concerning these omissions in some of the more basic classes like Point and Rect? My code just looks rather bloated copying the members individually like this so I thought maybe I'm doing it wrong.

Thanks in advance for any guidance.

-- modified at 21:59 Saturday 7th January, 2006

ask one question in VC .NET

Pierre,Hsieh7-Jan-06 13:51

Pierre,Hsieh

7-Jan-06 13:51

I want to build a win32 console program in VC .Net. I wrote one function in random1.h and random1.cpp, Then, I wrote my main program in SimMCMain.cpp which call this function from random1.h and random1.cpp. It's no problem in VC++ 6.0, but it always has problem when linking in VC.Net. Can anyone give me some suggestion? Thanks

****random1.h***
#ifndef RANDOM1_H
#define RANDOM1_H

double GetOneGaussianBySummation();
double GetOneGaussianByBoxMuller();

#endif

****random1.cpp****
#include <cstdlib>
#include <cmath>

// the basic math functions should be in namespace
// std but aren't in VCPP6
#if !defined(_MSC_VER)
using namespace std;
#endif

double GetOneGaussianBySummation()
{
double result=0;

for (unsigned long j=0; j < 12; j++)
result += rand()/static_cast<double>(RAND_MAX);

result -= 6.0;

return result;
}

double GetOneGaussianByBoxMuller()
{
double result;

double x;
double y;

double sizeSquared;
do
{
x = 2.0*rand()/static_cast<double>(RAND_MAX)-1;
y = 2.0*rand()/static_cast<double>(RAND_MAX)-1;
sizeSquared = x*x + y*y;
}
while
( sizeSquared >= 1.0);

result = x*sqrt(-2*log(sizeSquared)/sizeSquared);

return result;
}

****SimMCMain.cpp ****
// requires Random1.cpp
#include <Random1.h>
#include <iostream>
#include <cmath>
using namespace std;

double SimpleMonteCarlo1(double Expiry,
double Strike,
double Spot,
double Vol,
double r,
unsigned long NumberOfPaths)
{
double variance = Vol*Vol*Expiry;
double rootVariance = sqrt(variance);
double itoCorrection = -0.5*variance;

double movedSpot = Spot*exp(r*Expiry +itoCorrection);
double thisSpot;
double runningSum=0;

for (unsigned long i=0; i < NumberOfPaths; i++)
{
double thisGaussian = GetOneGaussianByBoxMuller();
thisSpot = movedSpot*exp( rootVariance*thisGaussian);
double thisPayoff = thisSpot - Strike;
thisPayoff = thisPayoff >0 ? thisPayoff : 0;
runningSum += thisPayoff;
}

double mean = runningSum / NumberOfPaths;
mean *= exp(-r*Expiry);
return mean;
}

int main()
{
double Expiry;
double Strike;
double Spot;
double Vol;
double r;
unsigned long NumberOfPaths;

cout << "\nEnter expiry\n";
cin >> Expiry;

cout << "\nEnter strike\n";
cin >> Strike;

cout << "\nEnter spot\n";
cin >> Spot;

cout << "\nEnter vol\n";
cin >> Vol;

cout << "\nr\n";
cin >> r;

cout << "\nNumber of paths\n";
cin >> NumberOfPaths;

double result = SimpleMonteCarlo1(Expiry,
Strike,
Spot,
Vol,
r,
NumberOfPaths);

cout <<"the price is " << result << "\n";

double tmp;
cin >> tmp;

return 0;
}

PJ Arends7-Jan-06 14:02

PJ Arends

7-Jan-06 14:02

Pierre,Hsieh wrote:
but it always has problem when linking in VC.Net.

"You're obviously a superstar." - Christian Graus about me - 12 Feb '03

"Obviously ??? You're definitely a superstar!!!" - mYkel - 21 Jun '04

"There's not enough blatant self-congratulatory backslapping in the world today..." - HumblePie - 21 Jun '05

Within you lies the power for good - Use it!

Pierre,Hsieh7-Jan-06 14:14

Pierre,Hsieh

7-Jan-06 14:14

SimpleMCMain1 error LNK2019 and
SimpleMCMain1 fatal error LNK1120

PJ Arends7-Jan-06 14:44

PJ Arends

7-Jan-06 14:44

You really should supply more relevant information if you want useful help in solving your problem. Most people do not like playing "twenty questions" just to get enough information to help.

When the linker generates LNK2019 it gives you more info, what is the information given?

Pierre,Hsieh7-Jan-06 15:03

Pierre,Hsieh

7-Jan-06 15:03

Sorry, Because my system is chinese version and this is my first time to ask question in web site, that's why I didn't provide more information. I checked this error message from MSDN web site.

LNK2019 : unresolved external symbol 'symbol' referenced in function 'function'
SimpleMCMain1 error LNK2019: 無法在外部之程式庫中找到或連結所需之資料型別或函式的符號 _main，於函式 _mainCRTStartup 中參考

LNK1120 : number unresolved externals
SimpleMCMain1 fatal error LNK1120: 1 個無法在外部程式庫中找到或連結所需之資料型別或函式