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how to represent a negative number by bit?

 
Jello Yao
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Any one please help explain how to represent a negative number by bit? Please give a few examples. Thanks!
 
Pauline McNamara
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Hello Jello,
Though it makes for a nice rhyme, your display name doesn't quite fit the famous JavaRanch naming policy. Could you please take a minute to change your display name to show 2 names, preferably your real name. (It's all about maintaining our professional image - don't let the one-eyed moose fool you!).
Thanks and hope you'll be visiting the ranch often,
Pauline
 
Marilyn de Queiroz
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Any bit-type number that has a "1" in the highest position is negative.
 
Jello Yao
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What is the bit representation for -5? I know how to do it for 5(00000101). But I do not know how to do it for a negative number? Any tips?
Thanks!
 
boyet silverio
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follow the ff:
binary of decimal 5 00000101
change all 0 to 1, vice versa 11111010
add 1 00000001
========
corresponding value of -5 11111011

to check:
binary of -5 11111011
change 0 to 1, vice versa 00000100
add 1 00000001
========
results to binary of 5 00000101
[ January 05, 2003: Message edited by: boyet silverio ]
[ January 05, 2003: Message edited by: boyet silverio ]
 
Jello Yao
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Big thanks! I'm clear about this now.
 
Manish Hatwalne
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Have alook at this, and see if it is of any help.
HTH,
- Manish
 
John Lee
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In fact, the highest bit is a sign bite, only showing sign.
For example, for byte, there are 8 bites, but the range is from -2^7 to 2^7-1
2^7 - 1 = 0111 1111 ;
If you add 1 more, the highest bite will become 1, which means negative.
 
Jello Yao
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Big thanks!
 
John Lee
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You are welcome!
 
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