Berkeley CSUA MOTD:Entry 18245
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2017/12/15 [General] UID:1000 Activity:popular
12/15   

2000/5/12 [Computer/SW/Compilers] UID:18245 Activity:high
5/11    What happens if you increment past MAXINT?  Is this compiler
        dependent or is this standard behavior?
        \_ Short answer: overflow
           Roundabout answer: take 61C (shame on you if you've taken it and
           don't know.
           Hands-on answer: What would the bit pattern be for MAXINT?  It
           would be a single zero followed by n-1 ones on an n-bit machine.
           On a four-bit machine, this would be: 0111 (7 base 10)
           What happens when you add 1 to said bit-pattern?  You get a single
           one followed by n-1 zeros;
           Once again, on a four-bit machine, 1000 (-8 base 10)
           Note that C does not generate an error, cause an exception, etc.
           when overflow occurs.  This is a feature.
           -dans
           \_ are you saying that overflow (as you've specified) is standard
              behavior, that it's specified that this is the way it
              should happen when you increment past MAXINT?
                \_ C's specified behavior on integer overflow is
                   undefined (3.4.3 paragraph 3, 6.2.6.2 footnote 45,
                   6.5 paragraph 5, ISO 9899). but on many modern
                   machines with gcc and two's-complement arithmetic
                   you can expect that what dans has described will
                   happen.  -brg
2017/12/15 [General] UID:1000 Activity:popular
12/15   

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