C / C++ / MFC

14-Nov-07 21:31

hey ,i met with a problem here~ i wanna find a code snippet which can read the "*.hgt" file
does anyone know where i can get this?
thanks a lot Smile | :)

Nelek14-Nov-07 21:38

Nelek

14-Nov-07 21:38

The extension of a file is not the problem to read a file. You can use CFile/CArchive or any other possibility to open almost all extensions. The most important things are: Which saving mode has it? Binary, plain Text, UNICODE... and how is the structure of saved data (i.e. The first 30 Bytes is a header where 4 parameters mean 4 different things, then come 30 Bytes for a string, after 10x1 Byte for unsigned shorts, then a 10x20 Bytes to a matrix of...)

I want to mean... can you be a bit more concrete?

BTW, have you tried google?

Greetings.

--------
M.D.V.

If something has a solution... Why do we have to worry about?. If it has no solution... For what reason do we have to worry about?

Help me to understand what I'm saying, and I'll explain it better to you

“The First Rule of Program Optimization: Don't do it. The Second Rule of Program Optimization (for experts only!): Don't do it yet.” - Michael A. Jackson

Wink | ;)

cindy_try14-Nov-07 22:13

14-Nov-07 22:13

first ,thank u for ur attention Smile | :)

yeah , you got the point~ "The most important things are: Which saving mode has it?"
and this is also where the problem lies ,thats i have no idea of whats the structure of this ".hgt" file Frown | :-(

someone told me perhaps its NASA Shuttle Radar Topography Mission files
but i am still not sure $Shucks | :-\$

Nelek14-Nov-07 22:23

Nelek

14-Nov-07 22:23

Then... I think ready code will be not easy to find, and without the structure and meaning of every data unit... practically impossible to code it. Good luck

cindy_try14-Nov-07 23:52

14-Nov-07 23:52

Nelek wrote:
I think ready code will be not easy to find

yeah i think so~
hehe thank u very much all the same Big Grin | :-D

Maximilien15-Nov-07 2:51

Maximilien

15-Nov-07 2:51

if you don't know what the file is, why would you want to open it ?

you just have a file with that extension and just have the urge toopen it ?

Maximilien Lincourt
Your Head A Splode - Strong Bad

cindy_try15-Nov-07 4:12

address of constant [modified]

15-Nov-07 4:12

hehe
all i know about this file is its a 3D map,i just have no idea what the structrue of this file is~~
however after i checked some websites i am partly sure its a Shuttle Radar Topography Mission file~
have u got any idea for this?
Smile | :)

George_George14-Nov-07 20:15

14-Nov-07 20:15

Hello everyone,

I have tried that even if I have multiple character pointer variables, if the content they pointed to are the same, they are allocated with the same value. So, I think from compiler point of view, the constant with the same content shares the single copy in memory?

Here is my test program in Visual Studio 2005.

<br />
// #include headers, like windows.h<br />
<br />
int main (int argc, char** argv)<br />
{<br />
	char* abc = "Hello";<br />
<br />
	char* abc2 = "Hello";<br />
<br />
	// the value (address) of abc is the same as abc2<br />
<br />
	return 0;<br />
}<br />

thanks in advance,
George

-- modified at 2:28 Thursday 15th November, 2007

Roger Broomfield14-Nov-07 20:27

Roger Broomfield

14-Nov-07 20:27

That is a compiler optimization that you shouldnt rely on. /Gf on the compiler commandline tells the compiler to "place a single copy of identical strings into the executable file" and /GF "the pooled strings are placed in read-only memory".

George_George14-Nov-07 20:32

14-Nov-07 20:32

Thanks Roger,

I have checked that I do not have /Gf defined. Here is project --> properties --> C/C++ --> Command line --> All options,

/Od /D "_MBCS" /Gm /EHsc /RTC1 /MDd /Fo"Debug\\" /Fd"Debug\vc80.pdb" /W3 /nologo /c /Wp64 /ZI /TP /errorReport:prompt

Any more comments?

I am using .c other .cpp in this case.

regards,
George

Roger Broomfield14-Nov-07 21:12

Roger Broomfield

14-Nov-07 21:12

/ZI = Program Database for Edit & Continue, in this case /GF becomes the default

George_George18-Nov-07 4:21

18-Nov-07 4:21

Thanks Roger,

My question is answered.

regards,
George

Iain Clarke, Warrior Programmer

Iain Clarke, Warrior Programmer14-Nov-07 23:31

14-Nov-07 23:31

George-so-good-you-named-yourself-twice,

As has been said, the answer depends on compiler flags. But I would strongly pretend to yourself that the answer is impossible to know, and not depend on it.

If you want two pointers to the same place, be explicit about it. Or some person who changes your code in three years (ie, you) will have no idea you intended them to be the same, and will break things.
Or you will upgrade to Visual Studio 2020 (in the year 2012) and the compiler will do different things and you'll get nasty to find bugs.

To save this you'll have to write more comments than the effort is worth.

Iain.

George_George18-Nov-07 4:24