What is “2's Complement”?

Question

I\'m in a computer systems course and have been struggling, in part, with Two\'s Complement. I want to understand it but everything I\'ve read hasn\'t brought the p

Answer 1

REFERENCE: https://www.cs.cornell.edu/~tomf/notes/cps104/twoscomp.html

I invert all the bits and add 1. Programmatically:

  // in C++11
  int _powers[] = {
      1,
      2,
      4,
      8,
      16,
      32,
      64,
      128
  };

  int value=3;
  int n_bits=4;
  int twos_complement = (value ^ ( _powers[n_bits]-1)) + 1;