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Hello, I am trying to improve the speed of a function which heavily using these functions.
template<class T><br />
T min(const valarray<T>& x);
and
INT abs( int n ); in math.h
and
int memcmp( const void *buf1, const void *buf2, size_t count );
Any better functions to be used other than these.
Thank you.
Sonork 100.41263:Anthony_Yio
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Try using memmove instead of memcpy.
As for abs(), try replacing it with this inline function:
inline int myAbs(int n) {
if (n < 0)
return -n;
else
return n;
}
That would be a lot quicker than a function call. There maybe more to the abs function than that, but I don't know the details.
As for min(), I've never seen that particular version of it before. If you are doing something thats computationally heavy on prepared data, you could sort the data ahead of time and then just pull out the first element, that'd be your min.
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<br />
void *p = 0;<br />
DWORD allocadd = 0x500000;<br />
<br />
p = VirtualAlloc((void *)allocadd, 0x1000, MEM_COMMIT , PAGE_READWRITE);<br />
<br />
if (p == 0)<br />
{<br />
DWORD err = GetLastError();<br />
}<br />
This code works fine under Windows XP, but on 2K I get an "ERROR_INVALID_ADDRESS" error. The memory page in question is free, I checked, but I can't allocate it! If I change the desired address to something like 0x502000, it will work. But I need to be able to choose the base address.
Please help!
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Hi,
The following example demonstrates how to commit a specific page of reserved addresses from the previous example to a page of memory.
/* Commit memory for 3rd page of addresses. */
lpPage3 = VirtualAlloc (lpBase + (2 * 4096),
4096,
MEM_COMMIT,
PAGE_READWRITE);
Notice that instead of specifying NULL for lpAddress, a specific address is given to indicate exactly which page of reserved addresses becomes committed to memory. Also, this page of memory is initially given PAGE_READWRITE protection instead of PAGE_NOACCESS as in the previous example. The return address from the function is the virtual address of the first pages of
committed addresses.
MSDN
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Hi all, I'm a Visual C++ newbie and I've never really built a GUI app before. Every example I see seems huge with all the menus/windows/etc.
I was wondering how best to organize an application. Would it be ok to create one project for the MDI part of an app and another project for the menu part?
I tried searching for tutorials on this but didn't come up with much. Any help would be greatly appreciated!
Thanks!!
-Eugene
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swollug wrote:
Would it be ok to create one project for the MDI part of an app and another project for the menu part?
That does not make too much sense. A complete Doc-View application in MFC has only about a handfull of classes (APP, Doc, Frame, View and a few others). To this comes your application logic. You quickly learn what to find where.
Additionally, MFC tries quite hard not to make a difference between a user clicking a button on the screen, selecting a menu entry and typing an accelerator.
You wont do any good by trying to separate these parts.
Who is 'General Failure'? And why is he reading my harddisk?!?
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The MFC App wizard will generate you a framework MDI application. This is probably the best place for you to start.
Michael
'War is at best barbarism...Its glory is all moonshine. It is only those who have neither fired a shot nor heard the shrieks and groans of the wounded who cry aloud for blood, more vengeance, more desolation. War is hell.' - General William Sherman, 1879
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Normally you create multiple projects for a couple of reasons, 1) create libraries or dlls for code reusability 2) separate base class code from higher level derived code and 3) for multi-component based projects such as a database and web app where you want one project to define the database and another to define the web functionality, before linking them together, perhaps via another project. Since a menu is a part of the GUI for the app, it should be defined in the same project, unless you are going to use the exact same menu in all your applications (doubt it) or are creating a generic menu class (which is doubtful since you are a beginner  ). If your using MFC, I would create an MDI app from the wizard and using the resource editor (greeny tab on the project view pane) create your menu items in there and read up on MSDN how to handle them when they are clicked, its quite easy really, once you've had a play I'm sure it will all make sense .
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I've wrote A NT Service Program which DownLoad the Whole Website via www.CodeProject/.../.../(all Link) From Internet.I've Big Problem in Internet COnnection which Connection Break Down,My Program is Can't Pending and Abort.And Connection is ReConnect,DownLoad From Starting Page.
How Can Pending on Current Page while Connection is Break-Down and Resuming From Last Page.
Please Help me....If U Can...
I'm Using MFC....
Thank U so Much
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Hi,
I can suggest to buy LARGE HDD to download all Internet
to your local computer.
This is Joke, I hope you understand it.
Real solution is in the saving state of your
download. After restoring connection you can
start it from the breakpoint.
Vitali
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Hi All,
I have a big problem..I want to open a new window link on the parent window instead of opening a new window..MSDN etc says do it like...
void Browser::OnNewWindow(BSTR URL, long Flags, BSTR TargetFrameName,
VARIANT* PostData, BSTR Headers, BOOL FAR* Cancel)
{
if (m_pBrowserApp) {
COleVariant varEmpty;
if (Cancel != NULL )
*Cancel = TRUE;
m_pBrowserApp->Navigate(URL, &varEmpty, &varEmpty, &varEmpty, &varEmpty);
}
}
but this thing is not working here..is there anything or anyone can help..I am in urgent need to do it..pls help...any help is highly appreciated..I have already posted it here in CP for 3 4 times already but there was no reponse...
Himanshu
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Are you using MDI or SDI? If so, check out document-view articles.
Are you using CHTMLView?
Sonork 100.41263:Anthony_Yio
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 Hi All,
I have a big problem..I want to open a new window link on the parent window instead of opening a new window..MSDN etc says do it like...
void Browser::OnNewWindow(BSTR URL, long Flags, BSTR TargetFrameName,
VARIANT* PostData, BSTR Headers, BOOL FAR* Cancel)
{
if (m_pBrowserApp) {
COleVariant varEmpty;
if (Cancel != NULL )
*Cancel = TRUE;
m_pBrowserApp->Navigate(URL, &varEmpty, &varEmpty, &varEmpty, &varEmpty);
}
}
but this thing is not working here..is there anything or anyone can help..I am in urgent need to do it..pls help...any help is highly appreciated..I have already posted it here in CP for 3 4 times already but there was no reponse...
himanshu
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I have this simple question about casting... take a look at the code snippet below:
Base * pBase;
Derived * pDerived;
pBase=new Base(1);
//DOWNCAST:
pDerived = dynamic_cast<derived*> (pBase); //Why did it NOT failed? Sure dynamic_cast supports "down-cast" but pBase is pointing to a "IN-complete" object.
//pDerived = (Derived*) pBase; //What's the difference between this sort of simple casting and dynamic_cast? I know that with simple casting, you can't down-cast. Does it mean that with up-cast, simple casting is just as good as dynamic_cast? I have a feeling that dynamic_cast will check at runtime if the object is complete/incomplete (simple casting don't do this) - and is thus safe. Is this the reason why we use dynamic_cast?
pDerived->m_nAge = 10; //Of course, this will crash.
Also, here's C4303 from MSDN:
"C-style cast from 'type1' to 'type2' is deprecated, use static_cast, __try_cast or dynamic_cast... C-style type casting or function-style casting is NOT SUPPORTED when using Managed Extensions for C++...."
>> I don't think it's NOT SUPPORTED - why the documentation states that it's not supported? I just did it in a C++ managed console application and it's just a warning - not error.
Thanks.
norm
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norm wrote:
pDerived = dynamic_cast (pBase); //Why did it NOT failed? Sure dynamic_cast supports "down-cast" but pBase is pointing to a "IN-complete" object.
It did not fail because dynamic_cast doesn't fail, it returns NULL when there is a bad cast. Also, the correct way is:
pDerived = dynamic_cast <Dervied*> (pBase);
norm wrote:
I have a feeling that dynamic_cast will check at runtime if the object is complete/incomplete (simple casting don't do this) - and is thus safe
You are correct.
Best regards,
Alexandru Savescu
P.S. Interested in art? Visit this!
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Alexandru Savescu wrote:
Also, the correct way is: ...
That's what he did  IE just didn't display it because it treated the <Derived*> as a tag because he didn't use < and >. If you look at the page source, it's there
I thought the same thing initially
Ryan "Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"
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with all the different ways of doing it... dynamic_cast, __try_cast.. seems to be the way to go since they provide mechanism to confirm that cast is indeed a valid one.
But, why not just to this the good old C-style cast?
ClassB{...};
Class A : public ClassB
{
...
};
ClassA * pA = (ClassA*) new ClassB;
is the only reason why we don't do this no more is that C-style cast don't do run-time check?
norm
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i'd like to have some documents about programming. i'm learning two subjects : "Artificial Intelligence" and "Graphics" in DOS in C and C++
please help me
thanks for your reading ;P
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i'd like to have some documents about programming. i'm learning two subjects : "Artificial Intelligence" and "Graphics" in DOS in C and C++
please help me
thanks for your reading;P
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I'm having trouble getting the following program to compile. I'm trying to write a program that will generate a random number (say our of 150 numbers for example). What am I doing wrong? My error message is 2601. I'm defining something wrong it appears.
<br />
#include <stdlib.h><br />
#include <iostream.h><br />
<br />
void main()<br />
{<br />
<br />
int nrand (int n)<br />
<br />
{<br />
<br />
int x = RAND_MAX / n;<br />
int r;<br />
<br />
do r = rand() / x;<br />
while (r >= n);<br />
cout<<r;<br />
return r;<br />
<br />
}<br />
}<br />
Thanks, Dave
"The man who reads nothing is better educated than the man who reads nothing but newspapers."- Thomas Jefferson
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can you reformat the listing so it is easier to read ? (use the > < buttons below )
also, use srand to regenerate the random number generator (look in msnd for a full example)
Maximilien Lincourt
"Never underestimate the bandwidth of a station wagon filled with backup tapes." ("Computer Networks" by Andrew S Tannenbaum )
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Some of the most immediate problems are your #includes aren't correct. Also (unless you have a custom stdlib.h) there is a typo - your first include should be stdlib, not cstdlib. the #includes should look like #include <stdlib.h> (actually, you probably had it correct, but because they look like HTML tags to the server processor, they got stripped). Also namespace is a C++ specific feature but in C++ you can't have locally defined functions (your int nrand(int n). You'll need to break out your nrand and call it from your main.
Create a NRand class and header file and save them in their own source files. #include the header in your main source file. Then you'll need to call the class with an integer. I didn't even look at the logic contained in your loop. Try to get a good compile and then check back in!
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Look at my modification:
#include <cstdlib>
#include <iostream>
using namespace std;
int nrand (int n)
{
int x = RAND_MAX / n;
int r;
do r = rand() / x;
while (r >= n);
cout<<r;
return r;
}
void main()
{
}
Allan
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Hint: if you have a space before and after the < > they get not deleted by the stupid HTML-interpreter at CP.
I did find a few things in your program.
First:
In your main(), you need to seed the random-generator, or you will get the same list of random numbers over and over. Use srand() for that. You can find an example how to do it in the MSDN.
Second:
You should do the cout in your main, after the call to your nrand-function. Separates the logic in natural parts: nrand() gets you a number, but does not say what to do with it, and main() uses the number to do whatever must be done, but does not bother how to generate it.
Third:
Your main sould be of return type int, and you do return 0; if all went well, otherwise something different (right now cant see why you would want to return anything other than 0.
Who is 'General Failure'? And why is he reading my harddisk?!?
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