Hexadecimal: Difference between revisions

Revision as of 23:13, 26 August 2001

Revision as of 00:27, 27 August 2001

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BaseHexadecimal (often abbreviated ''hex'') is a base 16 [[number system]], which consists of symbols 0-9 and A-F. It is a useful system in [[computer|computers]] because there is an easy mapping from 4 [[byte|bytesbit]]s to a single hex digit. Thus one can represent every [[byte]] as a two consecutive hexadecimal digits.

For example:

0001 = 1

0010 = 2

0011 = 3

0100 = 4

...

1010 = 10

1011 = A

...

1111 = F

0001 = 1

0010 = 2

0011 = 3

0100 = 4

...

1001 = 9

1010 = A = 10

1011 = AB = 11

...

1111 = F = 15

So the the binary representation for 79 (0100 1111) can be written as 4F.

There are many ways to denote hexadecimal numbers. One (derived from [[C programming language|C]]) is to start with '0x'. [[Pascal programming language|Pascal]] programmers would indicate hex by an appended 'h'. Sometimes a prefixed dollar symbol signals a hexadecimal number. When numbers of various bases are used together, the base is often noted in a subscript of the number.

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[[Hex]] is an abbreviation of Hexadecimal.

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So the counting is as follows: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F, 10, 11, .. 19, 1A, 1B, ..., 1F, 20, ..., 9F, A0, ...

In texts there are several ways to denote hexadecimal numbers. One (derived from [[C]]) is to start with '0x'. Another way (from [[Pascal programming language|Pascal]]) is to end the numbers with a 'h'. So, 20h is the same as 0x20, which equals 32 in [[decimal counting]].

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The word "hexadecimal" is strange in that "hexa" is derived from Greek and "decimal" is derived from Latin. The original term was the fully-Latin "sexidecimal", but that was changed because some people thought it to be too racy.