hex in char arrays :S

I have something like this

Code:

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char something[] = {'\x00', '\x02', '\x05', '\xB4', '\x06', '\x1A', '\xB5', '\x3D', '\xB0', '\x4A', '\x9E', '\x67', '\x6C', '\xE0', '\x57', '\x4A', '\x61', '\x73', '\x01', '\x00', '\x00', '\x40', '\xC2', '\x18', '\xDE', '\x54', '\x19', '\xDE', '\x35', '\xA8', '\x61', '\x00', '\x00', '\x57', '\x41', '\x43', '\x43', '\x00', '\x41', '\x72', '\x65', '\x73', '\x4C', '\x69', '\x74', '\x65', '\x20', '\x31', '\x2E', '\x38', '\x2E', '\x31', '\x2E', '\x32', '\x39', '\x34', '\x34', '\x00', '\xC0', '\xA8', '\x01', '\x64', '\x18', '\xB8', '\xCA', '\xC1', '\x03', '\x00', '\x04', '\x00'}

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I am using VC++, I tried adding a '\0' to the end it also didnt work. The problem is if i do something simple like char something[] = {'\x39'}; that would assign the ascii character. But when i did that big thing up there and outputted it to some edit box just to check if it assigned correctly it didnt print anything. Please help, thanks

To represent hex you must use 0x in front of the hex number.
So this would represent two hex numbers with the values 0 and 2

Code:

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        char something[] = {'\0x00', '\0x02'};

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So i which should i use?
char Something[] = {'\0x00'};
char Something[] = {'0x00'};
char Something[] = {'\x00'};

Quote:

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Originally Posted by Elyubarov

So i which should i use?
char Something[] = {'\0x00'};
char Something[] = {'0x00'};
char Something[] = {'\x00'};

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You should use this form

Code:

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char Something[] = {'0x00'};

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Here are some links that might help.
The links also give a little info on this form '\x00'
C++ Integer Constants

http://msdn.microsoft.com/library/en..._constants.asp

Character Escapes
http://msdn.microsoft.com/library/en...terescapes.asp

that msdn thing didnt help at all since i cant understand how they explain things, anymawho
can i do
char something[] = {'0x00', '0x39'};
^as an example, with alot more chars.
EDIT:
Why wont this work then?
char something[] = {'0x44', '0x00', '0x02', '0x05', '0xB4', '0x06', '0x1A', '0xB5', '0x3D', '0xB0', '0x4A', '0x9E', '0x67', '0x6C', '0xE0', '0x57', '0x4A', '0x61', '0x73', '0x00', '0x00', '0x00', '0x40', '0xC2', '0x89', '0xBA', '0xA4', '0x91', '0xC0', '0xE6', '0xA8', '0x61', '0x00', '0x00', '0x57', '0x41', '0x43', '0x43', '0x00', '0x41', '0x72', '0x65', '0x73', '0x4C', '0x69', '0x74', '0x65', '0x20', '0x31', '0x2E', '0x38', '0x2E', '0x31', '0x2E', '0x32', '0x39', '0x34', '0x34', '0x00', '0xC0', '0xA8', '0x01', '0x64', '0x18', '0xB8', '0xCA', '0xC1', '0x03', '0x00', '0x04', '0x00'};

Its not printing the hex that i specified, i dont know were it is getting it from , ascii of 0x44 is 'D' it is giving me '4'.

@Elyubarov: What is it that you want to obtain? Why hex instead of decimal? Are you trying to store the representation or the value?

@Anubis: Please make sure you test your advice before giving it:

Code:

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char something[] = {'0x00'};

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produced the following:

Quote:

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warning: multi-character character constant

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and of course it produced undefined output.

it doesnt have to be hex, i could use some online thing to convert it to decimal, does that make a difference? [sorry about the double post i got this reply after i posted the other]

Ok so you want the values right? Basically it sounds like you want an array of small integers? Is this what you are trying to do?

Edit:
Or do you just want to initalize a string using the character's value instead of a string literal?

Quote:

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Or do you just want to initalize a string using the character's value instead of a string literal?

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^that one

Ok then ;)

Code:

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char name[] = "Bob";

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Would be:

Code:

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char name[] = { 0x42, 0x6f, 0x62, 0x00 };

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Of course this will only work on systems that have the same values for those letters.

The problem was that you were confusing the representation (using ' ' ) with the value. When you have the representation you use ' ' (or " " in the case of string literals). When you have the value you just put in the value.

char something[] = {0x44, 0x00, 0x02, 0x05, 0xB4, 0x06, 0x1A, 0xB5, 0x3D, 0xB0, 0x4A, 0x9E, 0x67, 0x6C, 0xE0, 0x57, 0x4A, 0x61, 0x73, 0x00, 0x00, 0x00, 0x40, 0xC2, 0x89, 0xBA, 0xA4, 0x91, 0xC0, 0xE6, 0xA8, 0x61, 0x00, 0x00, 0x57, 0x41, 0x43, 0x43, 0x00, 0x41, 0x72, 0x65, 0x73, 0x4C, 0x69, 0x74, 0x65, 0x20, 0x31, 0x2E, 0x38, 0x2E, 0x31, 0x2E, 0x32, 0x39, 0x34, 0x34, 0x00, 0xC0, 0xA8, 0x01, 0x64, 0x18, 0xB8, 0xCA, 0xC1, 0x03, 0x00, 0x04, 0x00};
^why does this only produce the letter 'D'(0x44), and nothing more. by the way, I appreciate all the help!

Remember that you are working with a null terminated string. Basically as soon as it sees the null character it stops reading the string. The null character has a value of 0. What is the second value in the array?

>why does this only produce the letter 'D'(0x44), and nothing more.
Because you told it to:

Code:

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char something[] = {0x44, 0x00

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heh, im a n00b:-p, but I need that 0x00 since Im sending this as a packet and the server at the other end interprets the packet in a strict way, it reads the 0x00 as a 'seperator', so what should i do?

>so what should i do?
Stop trying to use a C-style string and figure out another way to determine the length. For example, send the size of the string first, then the string itself, and don't try to use functions that expect a null terminated string.

I did not make the server so i cant change what packets it accepts, I am not sending this in hex because i need the length i would just use the strlen() operator. I am sending it in hex because its some pretty weird ascii chars and i dont think vc++ would accept them, can i do it in a string literal with ascii chars(that are weird)?

Using a string literal would not solve your problem. The null character is there, and that's all there is to it. Prelude's advice is right on. The only way you're going to do this without changing what the servers excpects as input is to use functions that don't work with null-terminated strings. There're a number of different types of strings. The one Prelude is suggesting is quite easy to work with. It's just an array of chars, and a separate integer storing the number of elements in that array.

uhmm can you give me an example, i dont understand what your getting at if i try:
char something[0] = "a";
char something[1] = "b";
I get a redefinition error.

It's as simple as:

Code:

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char something[] = "string literal";

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But you don't seem to be paying attention to what we tell you if you're still going on about using a string literal instead of an initialization list.

Stop confusing me, what should i use? :'(

That's because when you declare an array, you need to declare all of the elements

Code:

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char something[2]

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and then work with individual ones

Code:

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something[0] = 'a'
something[1] = 'b'

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You'd probably also run into problems using double quotes (") for a char. Double quotes are for strings. Use single quotes.

An example:

Code:

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int length = 80;
char string[length];
int i = 0;
while( i < length) string[i] = '\0';

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This code creates a string of 80 null characters without a problem. The problem comes when you use standard output functions to send this string, as they will stop at the first null character. This is why you need to read Prelude's post. Her solution works, and is probably the easiest one.

Quote:

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Stop confusing me, what should i use? :'(

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We're not confusing you. We're trying to help you. You've been told exactly what you need to do.

Quote:

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Stop trying to use a C-style string and figure out another way to determine the length. For example, send the size of the string first, then the string itself, and don't try to use functions that expect a null terminated string.

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Beyond this, that's all we can tell you, because to find a complete solution and tell you what functions / APIs to use, we'd need to know the whole situation, and you're unlikely to find someone willing to take the time to do this. Can you contact the server administrator?

I have char something[50]; then
char something[0] = 'a';
and i get : error C2466: cannot allocate an array of constant size 0 and
error C2075: 'something' : array initialization needs curly braces and
error C2369: 'something' : redefinition; different subscripts

Code:

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char something[0] = 'a';

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Remove the word char. You're not declaring it, you're defining it.

Your first, second and probably third errors will be solved by this, because it thinks you're declaing something, and you can't declare and array of size 0.

It appears to me that you have not yet mastered all of the basics of C++. Perhaps you should write some simpler programs before attempting networking and complicating Windows programming, as you have been doing.

still when i have something and do something[5] = ' ', the hex of " " is 0x20 not 0x00

If you want to represent 0x00, you use '\0'. The space is represented as a different ASCII character. Apparently as 20 hex.

'\0' terminates the string.

So does 0x00. They're the same thing.

I want it to not terminate....

How many times have we told you? Use functions that use an array of chars and a variable holding the array length, instead of functions that use a null character to terminate the string!



edit: Unless someone here can already suggest an alternate string API, do a search on google for string API's. They should advertize the fact that they use this alternate method.

Quote:

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Originally Posted by Elyubarov

I did not make the server so i cant change what packets it accepts, I am not sending this in hex because i need the length i would just use the strlen() operator. I am sending it in hex because its some pretty weird ascii chars and i dont think vc++ would accept them, can i do it in a string literal with ascii chars(that are weird)?

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if you're sending something to a server you can be sure the server is expecting you to tell it how many bytes you are going to be sending it. otherwise it won't know when to quit accepting data from you. read the server documentation to find out the format in which you send it data.

there is no documentation, I making a client for a program, I packet sniffed. Anyways, the string was always there its just when i put it in a MessageBox() the MessageBox didnt read past the NULL(0x00), but when i sent it through a socket it was ok, i just could not use strlen(), one more question: does sprintf() stop at the NULL as well, because i am having trouble with it.

>does sprintf() stop at the NULL as well
Yes. Most functions that expect a C-style string will use the null character as a sentinel. If it's not there then you risk undefined behavior.

You can work with your strings manually, char by char. It requires a lot of loops, etc.. but once you've done a couple of simple operations it's really quite easy. the send() function in Winsock (and I imagine the same is true in other APIs), a buffer is sent as a parameter, with an integer telling the length - that's the type of string we've been telling you to use for quite some time now. Depending on where you get this string from originally, if you use this type of string all along, strlen() is probably not necessary.