C / C++ / MFC Discussion Boards

Kamis1-Jul-04 0:02

1-Jul-04 0:02

Well,I look into limits.h and see that "short" consists of 2 bytes on my machine and there are 4 bytes for "int" type. So,
1) what does it depend on? (OS, compiler, CPU)
2) Suppose I use such a variable in my prog:
short a;
a=32000;
and than run it on the machine where "short" consists of 1 byte. Will it work correctly?

Re: type size [edited]

bneacetp1-Jul-04 0:17

bneacetp

1-Jul-04 0:17

1) From my understanding, the size of the variable depends on the compiler and/or OS (whether 16bit-, 32bit-, or 64bit-based I think).
2) If you ever ran into a situation where a short took only a byte, you wouldn't be able to get a to 32000. The highest number you could get to would be 255. Look below at the binary math:

1111 1111

1 + 2 + 4 + 8 + 16 + 32 + 64 + 128 = 255

I doubt though that you will ever run into a situation where a short will only take a byte of memory. I hope that this helps.

Happy Programming and God Bless!

"Your coding practices might be buggy, but your code is always right."

Internet::WWW::CodeProject::bneacetp

Re: type size

Antony M Kancidrowski1-Jul-04 0:29

Antony M Kancidrowski

1-Jul-04 0:29

NO! The maximum number you can get in 8 bits is 255

1 + 2 + 4 + 8 + 16 + 32 + 64 + 128 !!!

Ant.

I'm hard, yet soft.
I'm coloured, yet clear.
I'm fuity and sweet.
I'm jelly, what am I? Muse on it further, I shall return! - David Williams (Little Britain)

No - Int is signed

normanS1-Jul-04 2:38

normanS

1-Jul-04 2:38

Being pedantic, INT is a signed value.

For an 8-bit value, the range is 0000 0000 to 1111 1111.

BUT . . . 0000 0001 to 0111 1111 are positive, while for 1000 0000 to 1111 1111, the sign bit (MSb) is 1, so these are negative numbers.

The range is thus -128 to +127 for a 1-byte INT.

10 or 15 years ago, I did some development on Windows 3.11 using Turbo C++ 3.1 (16-bit Integers.) I carefully used only ANSI C commands, for portability, but I also used INTs, instead of SHORT & LONG. This really caused problems when I ported the code to a MicroVax running VMS (32-bit INT, as I recall.)

Re: No - Int is signed

Antony M Kancidrowski1-Jul-04 5:15

Antony M Kancidrowski

1-Jul-04 5:15

NormanS wrote:
Being pedantic, INT is a signed value.

Quite, though I was pointing out the mistake in binary mathematics. Still my statement stands as I do not metion type Wink | ;)

Ant.

I'm hard, yet soft.
I'm coloured, yet clear.
I'm fuity and sweet.
I'm jelly, what am I? Muse on it further, I shall return! - David Williams (Little Britain)

Re: type size

Graham Bradshaw1-Jul-04 0:43

Graham Bradshaw

1-Jul-04 0:43

Kamis wrote:
what does it depend on

The ANSI standards do not impose any restrictions on the size of short, int or long data types, and for portable code, you should make no assumptions. Famously, some (many) years ago, the Microsoft C++ compiler changed the size of an int from 2 bytes to 4 bytes, and broke all sorts of code (including a lot of internal MS stuff), that had hard-coded the assumption that sizeof(int) was 2.

In the Windows world, if you need a guaranteed size, you can use BYTE, WORD and DWORD data types.

If you need code to be portable, you have to make use of sizeof() and all of the #defines in limits.h and/or other header files.

Re: type size

Kamis1-Jul-04 1:25

Kamis

1-Jul-04 1:25

Thanks for the help!

Re: type size

Henry miller1-Jul-04 3:04

Henry miller

1-Jul-04 3:04

Once upon a time, in a land not so very far from here there was a machine. This machine seems just like any other computer at first glance, but when you look closer you discover the size of short, int, and long are all 36 bits!

Don't make any assumptions lest you one day be called upon to port you code to that machine.

You can of course decide how far to go. If your program is using MFC you can be confident that porting to non-windows won't happen, so you only need to consider windows. Microsoft is unlikely to make short less than 16 bits, but it might be bigger.

In general it is safe to assume that short is 16 bits because any machine where that is not the case will either have more bits, or other serious limitations that you have to take into account from the start of design. (they still make 4 bit CPUs, but the code that runs on them is all written in house)

More important these days is to note that sizeof(int) is no longer == sizeof(VOID *). This is breaking a lot of code, 64 bit CPUs are here today some people even have them on their desktop without knowing it. (though windows doesn't use all 64 bits yet, that will come)

Re: Searching for Font (GDI+)

Mike Dimmick1-Jul-04 0:13

Mike Dimmick

1-Jul-04 0:13

You can use GDI and GDI+ in the same application. You can continue to use the GetFontUnicodeRanges API. You can call Graphics::GetHDC to get a GDI HDC from a GDI+ Graphics object. Call Graphics::ReleaseHDC to unlock it when you're finished.

Stability. What an interesting concept. -- Chris Maunder

Re: Searching for Font (GDI+)

Slava20001-Jul-04 0:45

Slava2000

1-Jul-04 0:45

Thank you very match, but i want to avoid a duplucate Windows object HFONT (once as member of GDI+ Font class, and secong HFONT, that i need to select (SelectObject) into HDC for forwarding HDC to GetFontUnicodeRanges):

<br />
Status st=Ok;<br />
INT nFound=0;<br />
InstalledFontCollection InstalledFonts;<br />
INT nCount=InstalledFonts.GetFamilyCount();<br />
FontFamily *pInstalledFamilyes=new FontFamily[nCount];<br />
st=InstalledFonts.GetFamilies(nCount,pInstalledFamilyes,&nFound);<br />
ATLASSERT(st==Ok);<br />
<br />
//Create a font and test it...<br />
for(INT i=0;i<nFound;i++)<br />
{<br />
	BOOL bFontFound=FALSE;<br />
	Font FoundFont(&pInstalledFamilyesi],fontSize,FontStyleRegular,UnitPixel);//First creation<br />
	if(FoundFont.GetLastStatus()!=Ok)<br />
		continue;<br />
	//Create a GDI object HFONT for using WINAPI functions for serching font<br />
	LOGFONTW lf;<br />
	FoundFont.GetLogFontW(pGr,&lf);<br />
	HFONT hFont=::CreateFontIndirect(&lf);//Second creation<br />
	ATLASSERT(hFont);<br />
<br />
	WTL::CDC dc;//One more HDC<br />
	dc.CreateCompatibleDC(pGr->GetHDC());<br />
	<br />
<br />
	HFONT hOldFont=(HFONT)::SelectObject(dc,hFont);<br />
<br />
	//Get the glyphsets array for a font<br />
	GLYPHSET *pGlSet=NULL;<br />
	DWORD nSize=::GetFontUnicodeRanges(dc,pGlSet);//Retrieve a size of an array<br />
	if(nSize==0)<br />
		continue;<br />
	pGlSet=new GLYPHSET[nSize];<br />
	::GetFontUnicodeRanges(dc,pGlSet);//Fill the array<br />
<br />
	pGr->ReleaseHDC(dc);<br />
//........................................ etc.<br />

So can i to avoid duplicate creation of the tested font.

Thanks.

displaying the mem address of chars + char arrays

Member 121044230-Jun-04 23:34

Member 1210442

30-Jun-04 23:34

I can do the following with 'int' with ease:
1: get the address of the pointer
2: get the contents of the pointer (the address it points too)
3: get the value of the variable pointed too.

int *a;
int b = 'B';

cout <<"address of b (the var) = " <<&b <

Re: displaying the mem address of chars + char arrays

Yogesh Kshatriya1-Jul-04 0:25

Yogesh Kshatriya

1-Jul-04 0:25

Modify the code as follows.
It should serv your purpose.

void main(){

char *a;
char b = 'B';

a = &b;

cout <<"address of a = " <<&a <

Re: displaying the mem address of chars + char arrays

Member 12104421-Jul-04 1:37

Member 1210442

1-Jul-04 1:37

Can you please explain this to me:

(unsigned long)(*(&a))

thanks D'Oh! | :doh:

Re: displaying the mem address of chars + char arrays

Yogesh Kshatriya1-Jul-04 3:02

Yogesh Kshatriya

1-Jul-04 3:02

a contains address of b. But if you say cout << a, it won't print the contents of a ( i.e address of b).
But you know it is address i.e. unsigned long type, so force it to print conent of a as an address.

Actually referencing & derefrerncing in the statment is not required.

i.e (unsigned long)(*(&a)) is same as (unsigned long)(a)

Re: displaying the mem address of chars + char arrays

Member 12104422-Jul-04 0:31

Member 1210442

2-Jul-04 0:31

hmmm, yes that makes much more sense, thanks! Smile | :)

get list of tables

Yulianto.30-Jun-04 22:59

Yulianto.

30-Jun-04 22:59

I`m having problem on getting list of tables from ODBC data source. I use SQLTable, but it didn`t work. It think it`s the first parameter. does anybody knows what to pass to the first parameter( h_stmt)? Thank you. I hope this is a good question.

Smile | :)

Re: get list of tables

Antony M Kancidrowski1-Jul-04 0:23

Antony M Kancidrowski

1-Jul-04 0:23

The first parameter is a SQLHSTMT variable.

SQLHSTMT h_stmt;

I am unaware of any SQLTables examples BUT If you look at the example for SQLColumns[^] does that help?

If not can you post a snippet of the code you are trying to use.

Ant.

I'm hard, yet soft.
I'm coloured, yet clear.
I'm fuity and sweet.
I'm jelly, what am I? Muse on it further, I shall return! - David Williams (Little Britain)

Re: get list of tables

David Crow1-Jul-04 2:34

David Crow

1-Jul-04 2:34

See here.

"When I was born I was so surprised that I didn't talk for a year and a half." - Gracie Allen

Using the Clipboard

tunerica30-Jun-04 22:45

tunerica

30-Jun-04 22:45

I tried looking through a few of the articles that were given on the site about using the clipboard, but none of them really made sense to me or helped.

I am trying to make the following call:

frame1 = Clipboard.GetDataObject();

But I keep getting the following error:

error C2065: 'Clipboard' : undeclared identifier

Now I assumed that I had to add an include directive to fix this problem, however, after much searching through the MSDN I wasn't able to come up with anything. Any help with this problem would be very much appreciated.

Micheal

Re: Using the Clipboard

jmkhael30-Jun-04 22:54

jmkhael

30-Jun-04 22:54

tunerica wrote:
frame1 = Clipboard.GetDataObject();

Sounds like VB no?

Are you sure this[^] didnt help?

Papa

while (TRUE)
Papa.WillLove ( Bebe ) ;

Re: Using the Clipboard

tunerica30-Jun-04 23:12

tunerica

30-Jun-04 23:12

I'm using Visual C++, have I set it up as if I was using VB?

I did look at that article but couldn't really get anything from it.

To explain further what I am trying to do, I have used the function capEditCopy to put a frame from the video buffer to the clipboard. I wanted to assign that data to frame1 which is an IDataObject. If anyone knows a better way to do it, I would be happy to give it a try. But if you tell me what my error is that would be even better.

Micheal

Re: Using the Clipboard

Mike Dimmick1-Jul-04 0:26

Mike Dimmick

1-Jul-04 0:26

OleGetClipboard( &frame1 );

Stability. What an interesting concept. -- Chris Maunder

Touch Screen Help!

Renjith Ramachandran30-Jun-04 22:41

Renjith Ramachandran

30-Jun-04 22:41

we developed a point of sale software for desktop, now i want to
convert that in to touch screen enviornment.

Any idea..????

mind is everything.

Re: a POTouch Screen

palbano1-Jul-04 4:38

palbano

1-Jul-04 4:38

Sure why not Big Grin | :-D

I am not trying to be rude but I would think that a more senior member of CP would be able to pose a well formed question.

"No matter where you go, there your are." - Buckaroo Banzai

-pete

Re: a POTouch Screen

Renjith Ramachandran1-Jul-04 5:21

Renjith Ramachandran

1-Jul-04 5:21

sorry...actually my clipboard cheated me.!!!
also i was in a hurry...!!!

mind is everything.

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