Re: byte to hex string - C / C++ / MFC Discussion Boards

richiemac12-May-05 23:50

12-May-05 23:50

Hi all,

I'm a complete novice to C++.net and I'm in a spot of bother. I have some values that require certain calculations and conversions which I have no problem with at all. My problem arises when I try to store the values as hex strings. So, for example, I have a byte holding the value (in dec) 252. I want to hold the value as its hex equivalent in a string which will later be displayed in a textbox.

Does vs.net provide any built in functions for this task or, if not, how would I go about the conversion manually?

Any help gratefully recieved.

Re: byte to hex string

toxcct12-May-05 23:54

toxcct

12-May-05 23:54

char c = 252;
CString str;
str.Format("0x%X", c);

there, str contains the string "0xFC"

you could also use sprintf() and so on...

TOXCCT >>> GEII power
[toxcct][VisualCalc]

Re: byte to hex string

richiemac13-May-05 0:13

richiemac

13-May-05 0:13

I tried that already and just get the following error,

error C2664: 'System::String __gc *System::String::Format(System::String __gc *,System::Object __gc *)' : cannot convert parameter 2 from 'int' to 'System::Object __gc *'
Conversion from a built-in type or a value type to 'System::Object __gc*' requires boxing

Re: byte to hex string

toxcct13-May-05 0:51

toxcct

13-May-05 0:51

oh, your programming managed code.

well, what about this ?

char c = 252;
char str[100];
ssprintf(str, "0x%X", c);

TOXCCT >>> GEII power
[toxcct][VisualCalc]

Re: byte to hex string

richiemac13-May-05 1:37

richiemac

13-May-05 1:37

What I need to do is store the hex value as a string so I can set a textbox text element to that string. So I'm looking to do something like

 <br />
System::Byte b = 252;<br />
System::String* s = b (formatted as hex value);<br />

then

<br />
textBox1->Text = s;<br />

Does any of that make sense?? Smile | :)

Re: byte to hex string

David Crow13-May-05 2:15

David Crow

13-May-05 2:15

toxcct wrote:
ssprintf(str, "0x%X", c);

Shouldn't that be:

sprintf(str, "%#X", c);

"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

Re: byte to hex string

toxcct13-May-05 2:20

toxcct

13-May-05 2:20

for ssprintf -> sprintf, yes, i made a mistake

for 0x%X -> %#X, it is as you prefer...

TOXCCT >>> GEII power
[toxcct][VisualCalc]

Re: byte to hex string

itkid13-May-05 1:47

itkid

13-May-05 1:47

Hi Dear,
Just do the following
byte _val;
char _data[4]="";
sscanf(_data,"%x",&_val);

Regards
~Kid

Re: byte to hex string

David Crow13-May-05 2:19

David Crow

13-May-05 2:19

itkid wrote:
sscanf(_data,"%x",&_val);

Perhaps you meant sprintf() instead of sscanf().

"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

Re: byte to hex string

richiemac13-May-05 3:18

richiemac

13-May-05 3:18

Sorry still not working, getting the following,

error C3861: 'sprintf': identifier not found, even with argument-dependent lookup

if I use sscanf, same error with obvious replacements.

Re: byte to hex string

David Crow13-May-05 3:26

David Crow

13-May-05 3:26

The sprintf() function is part of stdio.h. I do not know if that set of APIs is available with VS.Net.

"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

Re: byte to hex string

richiemac13-May-05 4:02

richiemac

13-May-05 4:02

Can't seem to get it to work at all tbh. But eh, what do I know? Smile | :)

Surely .net must provide some way to format a string to dispay value in hex. Or you would think so!!

Re: byte to hex string

toxcct13-May-05 4:14

toxcct

13-May-05 4:14

ask this in the Managed C++ forum[^] instead so...

TOXCCT >>> GEII power
[toxcct][VisualCalc]

Re: byte to hex string

David Crow13-May-05 4:21

David Crow

13-May-05 4:21

Christian Graus might have a few articles in this regard.

"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

Re: byte to hex string

richiemac13-May-05 4:26

richiemac

13-May-05 4:26

I'll give it a go.

Cheers everyone for the help!

CMap lookup

rgchezhian12-May-05 23:19

rgchezhian

12-May-05 23:19

Hi,

I have to create a CMap and store N number of (CString,int)
and i want to look up using CString and return value would be int.

If any body have gone through this requirement pls let me know.
i am new to CMap.If anyother method exist also welcome.

regards
Chezhian

Re: CMap lookup

Jack Puppy13-May-05 0:49

Jack Puppy

13-May-05 0:49

<br />
#include <afxtempl.h><br />
<br />
CMap<CString, LPCTSTR, int, int> myMap;<br />
<br />
myMap.SetAt("one", 1);<br />
myMap.SetAt("two", 2);<br />
myMap.SetAt("three", 3);<br />
<br />
int nValue = 0;<br />
if (myMap.Lookup("two", nValue))<br />
{<br />
    TRACE(_T("value is %d\n"), nValue);<br />
}<br />

Pssst. You see that little light on your monitor? That's actually a government installed spy camera. Smile and wave to big brother!

Re: CMap lookup

rgchezhian13-May-05 1:59

rgchezhian

13-May-05 1:59

hi,

I tried this.

It gives the following errors

'myMap':UnKnown size
'myMap':Cannot be destroyed
'CMap':no appropriate default constructor available

Is any header has to include for this.

I am using vc++ 7.1 version?

Regards
Chezhian

Re: CMap lookup

David Crow13-May-05 2:21

David Crow

13-May-05 2:21

rgchezhian wrote:
Is any header has to include for this.

How about afxtempl.h.

"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

Re: CMap lookup

rgchezhian13-May-05 2:37

rgchezhian

13-May-05 2:37

It doesn't give any change in error

Re: CMap lookup

Jack Puppy13-May-05 13:28

Jack Puppy

13-May-05 13:28

I copied the code into 7.1 and it compiled fine.

I don't get those errors even if I don't include afxtempl.h. It almost sounds like you've created your own CMap class within the project. If so, that would be a problem.

Here's what I did to test the code:

1) File -> New -> VC++ Projects -> Win32 -> OK
2) Application Type = Console Application
3) Make sure Add support for MFC is checked
4) Finish
5) Add the #include <afxtempl.h> statement below stdafx.h
6) Add CMap code to _tmain

Compiles fine.

Pssst. You see that little light on your monitor? That's actually a government installed spy camera. Smile and wave to big brother!

Re: CMap lookup

rgchezhian14-May-05 21:16

rgchezhian

14-May-05 21:16

i followed the same sequence and declared CMap variable.

CMap myMap;

But still it shows the following error

'myMap':UnKnown size
'myMap':Cannot be destroyed
'CMap':no appropriate default constructor available
'CMap' : use of class template requires template argument list

Re: CMap lookup

Jack Puppy14-May-05 22:20

Jack Puppy

14-May-05 22:20

The map class is templated, so you need to declare the key and value types in the declaration.

CMap<CString, LPCTSTR, int, int> myMap;
-> maps string keys to integer values

CMap<BYTE, BYTE, void*, void*> myMap;
-> maps BYTE keys to void pointer values...

CMap<int, int, CPoint, CPoint> myMap;
-> maps int keys to CPoint values

etc.

More info:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vclib/html/_MFC_CMap.asp

Pssst. You see that little light on your monitor? That's actually a government installed spy camera. Smile and wave to big brother!

Re: CMap lookup

Jack Puppy13-May-05 2:30

Jack Puppy

13-May-05 2:30

I forgot to format the angled brackets in my post, causing the #include statement to screw up.

David posted the correct #include

Pssst. You see that little light on your monitor? That's actually a government installed spy camera. Smile and wave to big brother!

Re: CMap lookup

rgchezhian13-May-05 2:35

rgchezhian

13-May-05 2:35

but i didn't inclucde #include

But it shows error

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