Thread: divide by zero

  1. #1
    Registered User
    Join Date
    Jun 2011

    divide by zero

    void main()
      int i=60;int j=0;
    this code was compiled with gcc 4.4.5 on Ubuntu, on execution an error message was thrown as "Floating point exception" But on changing datatype of j to float it produced "inf". I m not able to understand why it is not working same with j as int.

  2. #2
    Registered User
    Join Date
    May 2009
    "inf" is defined as part of the IEEE float standard. IEEE 754-2008 - Wikipedia, the free encyclopedia
    in other words the "inf" is not part of an int computer number standard.

    Tim S

  3. #3
    Registered User
    Join Date
    Apr 2006
    Because for IEEE floating point numbers, dividing a regular number by 0 yeilds inf.

    For integers, dividing by 0 generally causes an interrupt. There is no standard result that is used.
    It is too clear and so it is hard to see.
    A dunce once searched for fire with a lighted lantern.
    Had he known what fire was,
    He could have cooked his rice much sooner.

  4. #4
    Registered User
    Join Date
    Jun 2005
    If your compiler supports IEEE floating point, dividing by zero gives a "special" infinite value.

    The C standard does not actually require that floating point values be represented using IEEE standard formats. There are real compilers that do not use IEEE formats (and I remember using one compiler that only used IEEE floating point if enabled using a command line switch).

    Dividing by zero gives undefined behaviour according to the C standard. Which means any result is acceptable (reporting inf, crashing, etc). There is also no requirement for consistent behaviour between types.
    Right 98% of the time, and don't care about the other 3%.

    If I seem grumpy or unhelpful in reply to you, or tell you you need to demonstrate more effort before you can expect help, it is likely you deserve it. Suck it up, Buttercup, and read this, this, and this before posting again.

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