I have a cstring object str = "5043", now i want to convert to Hex and put it in UCHAR array like
UCHAR sample[2];
Sample[0] = 0X50
Sample[1] = 0X43
How can i do this? please advice me
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This might have already been answered in this thread: stackoverflow.com/questions/3381614/…David Z.– David Z.2012-04-20 08:13:55 +00:00Commented Apr 20, 2012 at 8:13
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As a possibility for widening the scope of this question, "cstring object str" -> "string". "UCHAR" -> "unsigned char", then just leave this as a C++ question.Adrian Conlon– Adrian Conlon2012-04-20 08:46:53 +00:00Commented Apr 20, 2012 at 8:46
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3 Answers
You can scan the hex values directly from the string using sscanf(), something like below:
UCHAR sample[2];
for ( int i = 0; i < str.length() / 2 ; i++) {
sscanf( (str.substr(i*2,2)).c_str(), "%hx", &sample[i]);
}
h is for short and x is for hexadecimal obviously.
Also, this assumes that the UCHAR array is declared to be half as large as the string size.
Comments
Have you tried strol? It seems a little low tech, but should do the trick. Don't forget to pass 16 as the base...
You'll need to combine it with a little bit shifting and bitwise anding to split the result into exactly what you require, but that should be straightforward.
Hope this helps,
2 Comments
Naruto
Actually, i have already got converted value but i just need to update to UCHAR variable
Adrian Conlon
Hmm, in that case, I think you need a different question! i.e. How do I split an integer into two bytes? (For a sixteen bit value) You probably need to right shift 8 bits for the high byte and bitwise and (&) with 255 for the low byte.
To make your code simpler, you may use an union, e.g.
union
{
UCHAR char_val[2];
long long_val;
};
CString str = "5043";
long_val = strtol(str.GetString(), nullptr, 16);
// use char_val here