Hi everyone,
just having a couple of question here. I had an unsigned char array, which suppose to store in hex format, which I usually print it out using %02X. I tried to do a strlen since it an char array, but I think the result was not wat I expected. So therefore I would like to check whether there is a way to caluated the length of the item store in the unsigned char array?
Don't you know the length when you fill the array?
All problems in computer science can be solved by another level of indirection,
except for the problem of too many layers of indirection.
– David J. Wheeler
Hi vart,
Actually I called the function through a dll file that was not coded by me. So therefore I wouldn't know the actual length of the output data.
I don't understand how it is possible to work with the array without knowledle about its length...
What is the API you are using?
All problems in computer science can be solved by another level of indirection,
except for the problem of too many layers of indirection.
– David J. Wheeler
I'm using vc ver 6. so I suppose should be win32
No - I mean what is the function prototype you are using to fill the array,
it should in some way indicate the array length used, or by returning this value or by putting some special stop symbol in the first unused element etc
All problems in computer science can be solved by another level of indirection,
except for the problem of too many layers of indirection.
– David J. Wheeler
If it's an actual array (a global one, maybe), you can use sizeof() on it; but that doesn't work with pointers.
Code:char s[BUFSIZ]; fgets(s, sizeof(s), stdin);
dwk
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[QUOTE=dwks]If it's an actual array (a global one, maybe), you can use sizeof() on it; but that doesn't work with pointers.
but if function fills it not till the end it will do no good
All problems in computer science can be solved by another level of indirection,
except for the problem of too many layers of indirection.
– David J. Wheeler
Right did u had your code something like as follow while calling your routineI had an unsigned char array, which suppose to store in hex format, which I usually print it out using %02X.
?????Code:unsigned char HexSte[10]; somefucnction(HexStr);
atleast if u could find out the unsigned char array name u could iterate through the array and find out the length. Is that something like this u doing
if it is something like that, then it is quite difficult.Code:somefucntion("0X1254F");
ssharish2005
True. However, if the function is reasonable, it has to give the user a way to determine how much data was stored. Either it fills the whole thing like I suggested, or it leaves a terminator of some kind (likely a NULL character). If it doesn't leave a terminator, perhaps it always returns the same number of characters.Originally Posted by vart
but if function fills it not till the end it will do no good
There are other options; the function might return the size separately, for example.
Of course, the function could be doing something I haven't thought of, or it might not be reasonable.
dwk
Seek and ye shall find. quaere et invenies.
"Simplicity does not precede complexity, but follows it." -- Alan Perlis
"Testing can only prove the presence of bugs, not their absence." -- Edsger Dijkstra
"The only real mistake is the one from which we learn nothing." -- John Powell
Other boards: DaniWeb, TPS
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That's why I tried to ask what is the functionn prototype to understand what is it doing
All problems in computer science can be solved by another level of indirection,
except for the problem of too many layers of indirection.
– David J. Wheeler
Right, and if the OP answered that question we might be better off . . . .
Well, %X is used for numbers, so you can't print a string with it. Print a string normally, with %s. If the string contains a number like "27" that you would like printed in hex as 1B, use sscanf("%X").Hi everyone,
just having a couple of question here. I had an unsigned char array, which suppose to store in hex format, which I usually print it out using %02X. I tried to do a strlen since it an char array, but I think the result was not wat I expected. So therefore I would like to check whether there is a way to caluated the length of the item store in the unsigned char array?
Post your code. Then we can stop making [semi-]educated guesses.
dwk
Seek and ye shall find. quaere et invenies.
"Simplicity does not precede complexity, but follows it." -- Alan Perlis
"Testing can only prove the presence of bugs, not their absence." -- Edsger Dijkstra
"The only real mistake is the one from which we learn nothing." -- John Powell
Other boards: DaniWeb, TPS
Unofficial Wiki FAQ: cpwiki.sf.net
My website: http://dwks.theprogrammingsite.com/
Projects: codeform, xuni, atlantis, nort, etc.
