help with Dynamic allocation in C. - C / C++ / MFC Discussion Boards

if u are using c++

double_var=static_cast<double>(float_var)

d=(double)f;
d=static_cast<double>(f);

Interesting. This always works for me:

<br />
d = f;<br />

you can do the following

float f = some_value;
.
.
.
double d = static_cast<double>(f);

think it should work!

And you will know my name is the Lord when I lay my vengeance upon thee.

Please anyone can help me how to set the default font for CRichEditCtrl.

Thanks Smile | :)

The Phantom

Is it possible to Hook the DDI funcion calls? How? Unsure | :~

Vikrams

Can I place a web browser control into the main window of a non Doc/View or non Dialog based application?

-- Steve

SteveBob wrote:
Can I place a web browser control into the main window of a non Doc/View or non Dialog based application?

You should be able to, but why makes things more difficult for yourself.

Have a look at the links here: http://www.codeproject.com/useritems/HTMLCtrlSample.asp?msg=452093#xx452093xx[^]

Neville Franks, Author of ED for Windows. www.getsoft.com
Make money with our new Affilate program

i've been working on this program (cryptology based) and just realized that the only way that it would be up to standards; would be to have a user defined lenght of the array of characters (captured by getchar() ). I am only in the 3rd month of my programming class, so we have not yet covered dynamic allocation (I don't know if we even will). I know that this is C++ but the people in C# said I should come here, you all are probably smarter anyway.
Long story-short. I need to capture an array of characters where, as the user types, the reallocation would be made; so no prompting of #'s just typing. here is how I tryed to do it but recived errors in execution, it does compile(What am I doing wrong??). I'm having a lot of trouble with this one. thanks bunches for your help Smile | :)

.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int char_to_num(char input);
void main (void){

char egrab,*cin;
int i,j,num,str_size;//, *t;

scanf("%c", &egrab); /*egrab grabs the enter from the previous
module this is a small part of my thing*/
printf("\nPlease enter the characters))>: ");
num = 0;
str_size=10;

cin= (char *)calloc(str_size, sizeof(char));

for(i=0; i<(i+1); i++,cin+=10)
{
for(j=0; j<10;j++,cin++){

*cin = getchar();
if (*cin =='\n')break;
num += 1;
}
if (*cin =='\n')break;
cin = (char *)realloc(cin, (sizeof(char)*10));

}
cin[i+j] = 0; /*close as to be printed as a string later*/

/*fill the array to be encrypted ( t[] ) with integer conversion*/

for(i=0; i<num;i++,t++,cin++){

*t="char_to_num(*cin);}

/*print" out="" the="" results="" as="" a="" check*=""

="" printf("\nnum="%d\n"," num);

="" for(i="0;" i<num;i++){
="" printf("%c",="" cin[i]);}

="" printf("\n");

="" i<num;i++,t++){
="" printf("%d="" ",="" *t);}

}="" *end*=""
="" ******************************************************************************************="" *this="" will="" convert="" character="" into="" number="" (67="" total="" possibilites)*=""

int="" char_to_num(char="" input){

="" int="" output;

="" if="" (="" (input="=" 'a')="" ||="" ){
="" output="1;}
" else="" if(="" 'b')="" 'c')="" 'd')="" 'e')="" 'f')="" 'g')="" 'h')="" 'i')="" 'j')="" 'k')="" 'l')="" 'm')="" 'n')="" 'o')="" 'p')="" 'q')="" 'r')="" 's')="" 't')="" 'u')="" 'v')="" 'w')="" 'x')="" 'y')="" 'z')="" input="=" '!'="" '@'="" '#'="" '$'="" '?'="" '^'="" '&'="" '*'="" '('="" ')'="" '-'="" '_'="" '=" ){
output = 39;}
else if( input == " +'="" '\\'="" '|'="" '`'="" '~'="" '.'="" ','="" '0'="" '1'="" '2'="" '3'="" '4'="" '5'="" '6'="" '7'="" '8'="" '9'="" '<'="">' ){
output = 59;}
else if( input == '[' ){
output = 60;}
else if( input == ']' ){
output = 61;}
else if( input == '{' ){
output = 62;}
else if( input == '}' ){
output = 63;}
else if( input == '/' ){
output = 64;}
else if( input == ';' ){
output = 65;}
else if( input == ':' ){
output = 66;}
else if( input == '%' ){
output = 0;}
else {
output = -1;}

return(output);
}

THANKS AGAIN.

/quick look

the problem is probably in your call to realloc() - the parameter specifies the new number of bytes the buffer should be, not the number of extra bytes you want.

you should also not use the variable name cin - it has special meaning in C++

and ditch the long if-else statement at the end! look at isalpha(), ispunct() and toupper(). A-Z are contiguous in ASCII so toupper(ch) - 'A' will map the letter in ch to a value between 0 and 25.

You should save yourself and your company years of grief by shooting yourself through the head immediately. Believe me, in the long run it'll turn out better for everyone. - Tyto (at arstechnica)

Awasu 1.0[^]: A free RSS reader with support for Code Project.

Thanks.I changed the 'cin' to 'ci' and adjusted the realloc to the following yet I cannot change the long if else statement because of my main program (long story involving multiplicative inverses of modular functions), so the realloc is now...

ci = (char *)realloc(ci, (/**/ sizeof(char) * (20+(10*i)) /**/) );

which should do what I want (realloc 10 char every loop if 10 or more are typed), yet I still recieve this:

"Expression: _CrtIsValidHeapPointer(pUserData) assertion failure"

, what on earth does that mean? I have a feeling that I have much more than just one problem. I must addmit though that this has become quite fun, so far in class i've picked up everything with ease, seeing how complicated C can get is really cool to me(even though i think that i have no idea how complicated C can get). anyway if you have ANY other ideas that would be great!

This error means that you've passed a pointer in to the system that wasn't given to you by the system.

You should save yourself and your company years of grief by shooting yourself through the head immediately. Believe me, in the long run it'll turn out better for everyone. - Tyto (at arstechnica)

Awasu 1.0[^]: A free RSS reader with support for Code Project.

Thanks for your help i've fixed the problem, i made a really dumb mistake. now comes the next point; so now how should i go about dynamicly declaring a n-dimentional array (i mean a nxn matrix, if my language was wrong)???

If you're not using the STL, the easiest way is to define a 1-D array and manually convert the 2-D co-ordinates to 1-D:

<br />
// initialize the array<br />
int width=10 ;<br />
int height=20 ;<br />
char* pArray = new char[ width * height ] ; <br />
<br />
// access a particular element<br />
int x=5 ;<br />
int y=2 <br />
char ch = pArray[ width*x + y ] ; <br />

You should save yourself and your company years of grief by shooting yourself through the head immediately. Believe me, in the long run it'll turn out better for everyone. - Tyto (at arstechnica)

Awasu 1.0[^]: A free RSS reader with support for Code Project.

Anyone know where to change the default file name extension for documents in VC7. It was part of the project setup in VC6, but I did not see it when I set up a new project in VC7. TIA.

Matt (Padawan Learner)

Check out the string table in the resource editor

Nish

Author of the romantic comedy

Summer Love and Some more Cricket [New Win]

Review by Shog⁹
Click here for review[NW]

Hi,

I am using an encrypted password in an INI file using the CryptoAPI (cryptography.cpp and .h) which is read from the INI file and converted back into text for checking by my program. However, certain symbols generated by the encryption cannot be read using GetPrivateProfileString() in Win95/98/Me. To get around this, I built an error-checker into my password encryption generator that writes the encrypted password to a test INI file and then tries to read it and decrypt it back again - if it fails, then it tells the user to pick another password. However, this is obviously flawed - because if the password generator is run on a Windows XP or 2000 system, it will never fail - but then when the program is run on Win95/98/Me, the decryption will fail.

So what I need to do is have my password generator check that the encrypted password will work on a Win95/98/Me system even if the generator is being run on an XP/2000 system. I hope I am explaining this okay. Essentially, what I want to do is force the program to act like it is running on a Win95/98/Me system even if it is being run on Windows XP or 2000. Is this possible by doing something like #define _WIN32?

Many thanks,
Keith

Why don't you convert the encrypted password to something printable before you write it to the INI file e.g. the hex values of each byte and decode it before decrypting. Then you won't have any problems at all.

From someone who uses INI files a lot Blush | :O

You should save yourself and your company years of grief by shooting yourself through the head immediately. Believe me, in the long run it'll turn out better for everyone. - Tyto (at arstechnica)

Awasu 1.0[^]: A free RSS reader with support for Code Project.

Hi, thanks for the reply. Sorry, but I'm not a very experienced programmer, I don't have a clue how to go about this. If you have any suggestions, I'd be very grateful.
Many thanks,
Keith

To encode, something like this:

unsigned char* pEncryptedBuf = ...
size_t encryptedBufLen = ...
for ( size_t i=0 ; i < encryptedBufLen , ++i )
    printf( "%02X" , (int)pEncryptedBuf[i] ) ;

You probably won't want to print the string to the console but this is the basic idea i.e. the string you store in the INI file is guaranteed to contain only nice characters and won't be a problem on any OS.

Decoding is left as an exercise for the reader... Smile | :)

You should save yourself and your company years of grief by shooting yourself through the head immediately. Believe me, in the long run it'll turn out better for everyone. - Tyto (at arstechnica)

Awasu 1.0[^]: A free RSS reader with support for Code Project.

Thanks a lot for this, I really appreciate the help. Unfortunately, I am such a novice I am still having problems (sorry). How would I use this code to convert an exising encrypted string (eg. encrypted_password_str) and store it in an INI file? I tried this:

char test_str[MAX_PATH];<br />
char test2_str[MAX_PATH];<br />
<br />
unsigned char* pEncryptedBuf = (unsigned char*)encrypted_password_str;<br />
size_t encryptedBufLen = sizeof(encrypted_password_str);<br />
for ( size_t i=0 ; i < encryptedBufLen; ++i )<br />
{<br />
	strncpy(test2_str,"",MAX_PATH);<br />
	itoa((int)pEncryptedBuf[i],test2_str,10);<br />
	strcat(test_str,test2_str);<br />
	WritePrivateProfileString("TestHex","TestHex",test_str,TestFile_str);<br />
}

But this prints odd characters to the INI file too, and I think I have totally screwed this up. Sorry if this looks incredibly stupid or obvious to you.

Many thanks,
Keith

I think you are trying to solve the wrong problem...
Why not do a base64 encoding of the encrypted password?

"was wir auch tun, wohin wir gehen
die illuminaten sind im system
sie kontrollieren überall
und 23 ist ihre zahl!"
23, welle: erdball

Hi, thanks for the reply. Sorry but I'm a bit of a C++ hack - ie. I'm a self-taught novice - so I'm not really sure what you mean. I've been doing a search on "base64 encoding" but can't seem to find anything that will help. Presumably this would put it into some form that could be placed in my INI file? If you could give me any advice on how to go about this I'd be really appreciative.

Thanks,
Keith

http://www.planet-source-code.com/xq/ASP/txtCodeId.1710/lngWId.3/qx/vb/scripts/ShowCode.htm
or do a google search for: base64 encoding

"was wir auch tun, wohin wir gehen
die illuminaten sind im system
sie kontrollieren überall
und 23 ist ihre zahl!"
23, welle: erdball

Why not store the encrypted password as a binary value in the registry?

Dave

Hi, thanks for the reply. I prefer to use an INI file (I'm using an INI file for all of the other settings anyway) - to be honest I've never really used the registry in my programming anyway, as I'm pretty much a hack - and a novice - when it comes to C++.
Many thanks,
Keith