Reversal of VkKeyScan? - C / C++ / MFC Discussion Boards

Re: pow(-1, 0.3333333333) doesn't return -1

Eguru1-May-04 20:46

1-May-04 20:46

I think it is because of this reason:
a^x = y
ln(a^x) = ln(y)
x.ln(a) = ln(y)
e^(x.ln(a)) = y

ln(a) is undefined for a <= 0

it should work for a,x,y are of type complex. I have done such a thing many years ago. It works also for -1 ^ 1/2 (which is the complex number "i" or "j") written as y.re=0 and y.im=1 .

I am not sure if pow can be called as "complex y = pow( complex a, complex x )", if not, you need to overload it in some way. That's a challenge!! Smile | :)

Wish it helps some.
Michel

Re: pow(-1, 0.3333333333) doesn't return -1

Roman Nurik2-May-04 4:08

Roman Nurik

2-May-04 4:08

thanks, i get what you're saying

i think maybe i will implement sets and complex numbers into my calculator program to get around this..

i've never heard of the "complex" class, though.. is it STL?

so far i'm only using STL classes and would like to keep it to a bare minimum of external libraries

r -€

Re: pow(-1, 0.3333333333) doesn't return -1

f642-May-04 6:59

f64

2-May-04 6:59

Hi,
Yes Complex is a class of STL, but it won't help you either, try this

complex<double> x, y, r;
x.real(-1.0);
x.imag(0.0);<br> <br>

y.real(1.0/3.0);
y.imag(0.0);<br> <br>

r = pow(x, y);<br> 
//r.real is -1.#IND00000
//r.imag is 0.0
//Still the same answer<br> <br>

r = exp(y * log(x));
//r.real is 0.5
//r.imag is 0.866025
//This is the answer Tim already gave you.

So as I said, you will have to do some preprocessing or redefine pow yourself

Fabian

Re: pow(-1, 0.3333333333) doesn't return -1

Roman Nurik2-May-04 7:04

Roman Nurik

2-May-04 7:04

thanks for the info... ill leave the fix for a later date

r -€

No static linking

jonsson_841-May-04 6:57

jonsson_84

1-May-04 6:57

I use Visual C++ 6.0. I want to link my MFC application staticly instead of using shared DLLs. If I go to Project->Settings->General I can ONLY chose "Use MFC in a shared DLL". What's wrong?

Re: No static linking

peterchen1-May-04 7:23

peterchen

1-May-04 7:23

linking to static MFC Libs is only available in VC6 Pro and above

Flirt harder, I'm a Coder

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Re: No static linking

PJ Arends1-May-04 14:16

PJ Arends

1-May-04 14:16

http://www.codeproject.com/dll/staticlink.asp[^]

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Reversal of VkKeyScan?

Abin1-May-04 5:31

Abin

1-May-04 5:31

::VkKeyScan translates a character to the corresponding virtual-key code and shift state for the current keyboard, but which function does the reverse and translates the VK code and shift state to a character, is there any? Thanks.

Re: Reversal of VkKeyScan?

User 66581-May-04 7:22

User 6658

1-May-04 7:22

http://www.gamedev.net/reference/programming/features/scan2asc/

this should help Smile | :)

regards

modified 12-Sep-18 21:01pm.

Re: Reversal of VkKeyScan?

Mike Dimmick2-May-04 0:14

Mike Dimmick

2-May-04 0:14

ToAsciiEx / ToUnicodeEx.

Stability. What an interesting concept. -- Chris Maunder

how to trap events and post it to a desired window

shammyrly1-May-04 4:57

shammyrly

1-May-04 4:57

i want to make a keyboard driver. my aim is to type any Indian languages in ms word or excel or notepad etc.what are the code words for hooking ( trap ) a key stroke and post it to a desired application. i have some idea first we have to get the focus of the window ( get focus api) then each keystroke has to be trapped and converted to their ascii. Then using post message api converted ascii is passed to the input focus window.
but i am not sure, pls give me a small program by which when we type 'a' in the keyboard we must get 'b' in the desired window. thanks

Re: how to trap events and post it to a desired window

Abin1-May-04 5:36

Abin

1-May-04 5:36

I think you will need to install a keyboard hook. Check ::SetWindowsHookEx.

How do I load a 16x16 icon?

Barvus1-May-04 4:38

Barvus

1-May-04 4:38

I'm trying to display a small icon in a CStatusBarCtrl. I created a 16x16 icon, IDI_X, in the resource editor, then I tried the following:

HICON hIcon;
hIcon = theApp.LoadIcon(MAKEINTRESOURCE(IDI_X));
m_wndSBC.SetIcon(0, hIcon);

The icon is resized to 32x32 and doesn't fit in the status bar. The CApp::LoadIcon documentation says it can only be used to load an icon whose size conforms to the SM_CXICON and SM_CYICON system metric. It says to use LoadImage instead. So, I tried this:

HANDLE hIcon;
hIcon = LoadImage(NULL, MAKEINTRESOURCE(IDI_X),
IMAGE_ICON, 0, 0, 0);
DWORD dwError;
dwError = GetLastError();

That didn't work either. LoadImage returns NULL and GetLastError returns 1813: "The specified resource type cannot be found in the image file."

Can anyone help?

Re: How do I load a 16x16 icon?

Barvus1-May-04 4:59

Barvus

1-May-04 4:59

Just an update. I got it to work by doing the following:

HANDLE hIcon;
hIcon = ::LoadImage(NULL, "res\\icon1.ico",
IMAGE_ICON, 0, 0, LR_LOADFROMFILE);
m_wndSBC.SetIcon(0, (HICON) hIcon);

But I'd still like to know why it didn't work the other way, if anyone can help.

Thanks.

Re: How do I load a 16x16 icon?

Michael Dunn1-May-04 6:06

Michael Dunn

1-May-04 6:06

LoadIcon() can only load 32x32 icons.
Specify the size in the LoadImage() call, 16x16 so the system knows which size you want.

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Re: How do I load a 16x16 icon?

Barvus1-May-04 6:25

Barvus

1-May-04 6:25

Hmmm... I'm still getting the same error 1831. What am I doing wrong? Confused | :confused:

m_hIconX = LoadImage(NULL, MAKEINTRESOURCE(IDI_X),
IMAGE_ICON, 16, 16, 0);
DWORD dwError;
dwError = GetLastError();

Re: How do I load a 16x16 icon?

Michael Dunn1-May-04 6:46

Michael Dunn

1-May-04 6:46

You need to pass the module handle of your EXE for the first parameter. In MFC you use AfxGetResourceHandle()

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Re: How do I load a 16x16 icon?

Barvus1-May-04 7:02

Barvus

1-May-04 7:02

Thanks, Mike! That did the trick. Much appreciated.

Re: How do I load a 16x16 icon?

f641-May-04 19:21

f64

1-May-04 19:21

Hi Barvus,
An unrelated coment to your problem, I saw you used GetLastError() just to check what was wrong with the LoadImage call, good news for you, you don't have to type those two lines ever again, you can check the registers and pseudoregister and see among other things, the last error directly, to better undestand what I'm talking about, check this article
An introduction to debugging in MSVC++ using Pseudoregisters
By Wouter Dhondt

Fabian

Re: How do I load a 16x16 icon?

Barvus1-May-04 20:05

Barvus

1-May-04 20:05

Hey, thanks for the tip! Good to know. I wonder why that's not documented in MSDN.... Or is it? Must be buried somewhere deep.

Re: How do I load a 16x16 icon?

f642-May-04 6:11

f64

2-May-04 6:11

It is!!!

Viewing the Last Error Code for the Current Thread

why doesn't run well about string type in this way?

vividtang1-May-04 2:15

vividtang

1-May-04 2:15

i want exercise iostream also support the file's input and output,so write the little program below,but after compile ,note"error C2065: 'String' : undeclared identifier",can you help me to solve it?
the program function is:read word from a text file named "in_file",and write every word into a output file named "out_file" .
#include<iostream.h>
#include<fstream.h>
#include<string.h>
int main()
{
ofstream outfile("out_file");
ifstream infile("password");
if(!infile)
{
cerr<<"error:unable to open input file!\n";
return -1;
}
if(!outfile)
{
cerr<<"error:unable to open output file!\n";
return -2;
}
String word;
while (infile>>word)
outfile<

Re: why doesn't run well about string type in this way?

Jijo.Raj1-May-04 2:46

Jijo.Raj

1-May-04 2:46

try

#include <string><br />
using namespace std;<br />
<br />
string word;

Regards,
Jijo. Wink | ;)

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Tomorrow is a mystery,
But today is a present.

Re: why doesn't run well about string type in this way?

vividtang1-May-04 4:00

vividtang

1-May-04 4:00

yes,but when to use namespace?
in addition,why to note "unable to open input file",in_file is a txt created by notepad?

Re: why doesn't run well about string type in this way?

Michael Dunn1-May-04 6:12

Michael Dunn

1-May-04 6:12

Reposting your includes:

#include <iostream.h>
#include <fstream.h>
#include <string.h>

You have a few problems here. First, you are using the old iostream headers instead of the STL ones. Change them to <fstream> and <iostream> without the .h extension.
Also, string.h is the C library header with the C-style string functions. You want to #include <string>
Next, the type is string not String.
And finally, as the other post said, you need to use the std:: namespace name before the types because STL types are in that namespace.

More details on the iostream vs. STL headers here[^]

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