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Confusion about negative number in binary

 
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Hi all,

I am confused about how to represent negative number in binary. For example, I think -1 is represented in binary as (32 bits int)1000..... 0001, but it doesn't seem right when I try -1 ^ 3, it gives me -4, can someone show me how is that calculated ? Thanks in advance.
 
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Negative numbers are represented as two's complement. To calculate the negate of the number, in bits, you first complement it (reverse all the bits) and then add 1.

So -1 --> 1111 1111 1111 1111 1111 1111 1111 1111

Another way to think about it is... if you add one to negative one you should get zero. If you add one to the number above, it should roll over to zero.

Henry
 
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Thank you Henry.
 
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