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Convert negative decimal to binary
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Hi, I'm having trouble trying to figure out a code that converts negative decimal numbers to binary, as well as specifying the number of bits. For example. convert -18 using 8 bits. This should come out as 10010010 doing it manually, I think. I'd appreciate the help, thanks.
Working with negative numbers in binary you need to use twos complement method. It is a bit confusing to start with (well it was for me). I use it a lot for checksum calculations. Hope this helps.
http://www.rsu.edu/faculty/PMacphers...rams/twos.html
David
http://www.rsu.edu/faculty/PMacphers...rams/twos.html
David
you can try Ex-Or ing the positive number with 10000000... it will work for numbers less than 01111111
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Check the preample of:
http://wiki.python.org/moin/BitwiseOperators
http://wiki.python.org/moin/BitwiseOperators
Should you find Irony, you can keep her!
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Newbie Poster
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Originally Posted by ALJ 
Hi, I'm having trouble trying to figure out a code that converts negative decimal numbers to binary, as well as specifying the number of bits. For example. convert -18 using 8 bits. This should come out as 10010010 doing it manually, I think. I'd appreciate the help, thanks.
Python Syntax (Toggle Plain Text)
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So in the manual, it says
How?! Specifically, how do they do this efficiently?
Jeff
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Of course, Python doesn't use 8-bit numbers. It USED to use however many bits were native to your machine, but since that was non-portable, it has recently switched to using an INFINITE number of bits. Thus the number -5 is treated by bitwise operators as if it were written "...1111111111111111111010".
Jeff
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Oh, nevermind. I thought it was saying something else. All it's saying is that when it performs right-shifts, it rolls in the MSB from the left. (Arithmetic instead of Logical shift)
I thought it was saying that it somehow represented negatives as if they had infinite precision, which would be impressive.
Jeff
I thought it was saying that it somehow represented negatives as if they had infinite precision, which would be impressive.
Jeff
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