If I have some array element, how can I get individual numbers from the array element buffer[0]?
For example, suppose I have buffer[0]=0x0605040302, I'd like to first extract 2, then 0, then 6, etc.
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You might want to edit your post. Use blockquote instead of code. Also what data type is buffer?Nobody– Nobody2010-08-09 11:56:26 +00:00Commented Aug 9, 2010 at 11:56
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Im surprised this question is upvoted.Zak– Zak2010-08-09 11:59:13 +00:00Commented Aug 9, 2010 at 11:59
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If i say buffer is unsigned long long int.How would you extract single digit from the array element.Unicorn– Unicorn2010-08-09 12:03:06 +00:00Commented Aug 9, 2010 at 12:03
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@Thej, you can extract single element by masking other elements.Praveen S– Praveen S2010-08-09 12:11:32 +00:00Commented Aug 9, 2010 at 12:11
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1I edited your question a bit for formatting and clarity, but ultimately I think you need to come up with a better title and refine your question a bit. You're looking for masking, and the fact the number is stored in an array has nothing to do with your actual question.Mark Elliot– Mark Elliot2010-08-09 12:14:23 +00:00Commented Aug 9, 2010 at 12:14
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1 Answer
The array element content is ONE number. You are trying to extract A DIGIT out of it. Look for masking and shifting - the & and >> operators.
EDIT:
A mask is a string of "0"s and "1"s that let you isolate bits of interest out of a number. A mask containing the hex digit 0xF is used to isolate individual hex digits in a number. For example:
num = 0x4321 (= 0100_0011_0010_0001)
mask = 0x00f0 (= 0000_0000_1111_0000)
num & mask = 0x0020 (= 0000_0000_0010_0000)
Shifting a number effectively brings the required bit to a required position in a number. So, shifting a number to the right by n positions will bring bit #n to place #0.
num = 0x4321 (= 0100_0101_0010_0001)
num >> 8 = 0x0043 (= 0000_0000_0100_0011)
Combine the two operations and you have your extracted digit!
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