Why float is called as 'float', not 'real'?

Discussion in 'C++' started by DirtyHarry, Mar 24, 2007.

  1. DirtyHarry

    DirtyHarry Guest

    Good day everyone. This sounds like a stupid question, but I became
    just curious yesterday, and I looked up several textbooks. However, no
    textbooks on computer language (that I have ) mentioned this. So I am
    asking to you, gurus...

    Is there any particular reason to call 'float' instead of 'real'?
    DirtyHarry, Mar 24, 2007
    #1
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  2. DirtyHarry

    ma740988 Guest

    On Mar 24, 12:13 am, "DirtyHarry" <> wrote:
    > Good day everyone. This sounds like a stupid question, but I became
    > just curious yesterday, and I looked up several textbooks. However, no
    > textbooks on computer language (that I have ) mentioned this. So I am
    > asking to you, gurus...
    >
    > Is there any particular reason to call 'float' instead of 'real'?


    What you call 'double' - real32?

    I'm certainly not well versed in the history of the languages ( I
    suspect this dates back to C ) nonetheless, Fortran is the only
    language I've encountered that used REAL. Granted, rational,
    irrational etc - numbers are approximations of real arithmetic, I
    suspect machine precision limitations plays an important role. Beyond
    that I'm unsure what the impetus is.
    ma740988, Mar 24, 2007
    #2
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  3. DirtyHarry wrote:
    > Good day everyone. This sounds like a stupid question, but I became
    > just curious yesterday, and I looked up several textbooks. However, no
    > textbooks on computer language (that I have ) mentioned this. So I am
    > asking to you, gurus...
    >
    > Is there any particular reason to call 'float' instead of 'real'?


    float stands for "floating point" as opposed to "fixed point". It is a
    more accurate description than "real" since not all real numbers are
    representable by a floating point number.
    Gianni Mariani, Mar 24, 2007
    #3
  4. DirtyHarry

    Jim Langston Guest

    "DirtyHarry" <> wrote in message
    news:...
    > Good day everyone. This sounds like a stupid question, but I became
    > just curious yesterday, and I looked up several textbooks. However, no
    > textbooks on computer language (that I have ) mentioned this. So I am
    > asking to you, gurus...
    >
    > Is there any particular reason to call 'float' instead of 'real'?


    So if we call a float a real, does that mean we have to call an int a fake?
    float is more descriptive I believe.
    Jim Langston, Mar 24, 2007
    #4
  5. DirtyHarry wrote:
    > Is there any particular reason to call 'float' instead of 'real'?


    Because a 'float' is not a real number, but a floating point number.
    There's a big difference.
    Juha Nieminen, Mar 24, 2007
    #5
  6. DirtyHarry

    SasQ Guest

    Dnia Fri, 23 Mar 2007 21:49:04 -0700, ma740988 napisa³(a):

    > Fortran is the only language I've encountered that used REAL.


    Pascal used it too ;)
    And it's probably the language used formerly by OP, causing
    his confusion upon encountering 'float' ;J

    --
    SasQ
    SasQ, Mar 24, 2007
    #6
  7. DirtyHarry

    Rolf Magnus Guest

    Jim Langston wrote:

    > "DirtyHarry" <> wrote in message
    > news:...
    >> Good day everyone. This sounds like a stupid question, but I became
    >> just curious yesterday, and I looked up several textbooks. However, no
    >> textbooks on computer language (that I have ) mentioned this. So I am
    >> asking to you, gurus...
    >>
    >> Is there any particular reason to call 'float' instead of 'real'?

    >
    > So if we call a float a real, does that mean we have to call an int a
    > fake?


    I guess the OP is talking about the mathematical term as in "real number",
    not the opposite of "fake".

    > float is more descriptive I believe.


    Agreed.
    Rolf Magnus, Mar 24, 2007
    #7
  8. DirtyHarry

    Rolf Magnus Guest

    DirtyHarry wrote:

    > Good day everyone. This sounds like a stupid question, but I became
    > just curious yesterday, and I looked up several textbooks. However, no
    > textbooks on computer language (that I have ) mentioned this. So I am
    > asking to you, gurus...
    >
    > Is there any particular reason to call 'float' instead of 'real'?


    Counter question: Is there any particular reason to call it 'real' instead
    of 'float'?
    Rolf Magnus, Mar 24, 2007
    #8
  9. DirtyHarry

    Pete Becker Guest

    DirtyHarry wrote:
    > Good day everyone. This sounds like a stupid question, but I became
    > just curious yesterday, and I looked up several textbooks. However, no
    > textbooks on computer language (that I have ) mentioned this. So I am
    > asking to you, gurus...
    >
    > Is there any particular reason to call 'float' instead of 'real'?
    >


    float is short for "floating-point." double is short for
    double-precision floating point.

    --

    -- Pete
    Roundhouse Consulting, Ltd. (www.versatilecoding.com)
    Author of "The Standard C++ Library Extensions: a Tutorial and
    Reference." (www.petebecker.com/tr1book)
    Pete Becker, Mar 24, 2007
    #9
  10. DirtyHarry

    ma740988 Guest

    On Mar 24, 8:43 am, Rolf Magnus <> wrote:

    > Counter question: Is there any particular reason to call it 'real' instead
    > of 'float'?

    I suspect the OP's thought process reflects what I - perhaps all of us
    - was taught in a mathematical sense. In that regard, I'd talk in
    terms of integers, real numbers and complex numbers. These are terms
    everyone understands including C / C++ programmers. I had a similar
    question hen I first encountered 'floats and double'. I'd like to
    believe Real32 and Real64 would suffice, but considering C/C++ has
    been around for sometime, you chalk it up to 'it is what it is' and
    move on.

    In the end, the OP could always - worse case - typedef the float/
    double to what he/she considers a more meaningful description. That's
    the beauty of the language.
    ma740988, Mar 24, 2007
    #10
  11. DirtyHarry

    Giff Guest

    Gianni Mariani ha scritto:

    It is a
    > more accurate description than "real" since not all real numbers are
    > representable by a floating point number.


    neither are all the integers by int...
    Giff, Mar 24, 2007
    #11
  12. Giff wrote:
    > Gianni Mariani ha scritto:
    >
    > It is a
    >> more accurate description than "real" since not all real numbers are
    >> representable by a floating point number.

    >
    > neither are all the integers by int...


    All integers from INT_MIN to INT_MAX are. For 'float' that is not so.

    V
    --
    Please remove capital 'A's when replying by e-mail
    I do not respond to top-posted replies, please don't ask
    Victor Bazarov, Mar 24, 2007
    #12
  13. DirtyHarry

    Greg Herlihy Guest

    On Mar 24, 8:58 am, "ma740988" <> wrote:
    > On Mar 24, 8:43 am, Rolf Magnus <> wrote:
    >
    > > Counter question: Is there any particular reason to call it 'real' instead
    > > of 'float'?

    >
    > I suspect the OP's thought process reflects what I - perhaps all of us
    > - was taught in a mathematical sense. In that regard, I'd talk in
    > terms of integers, real numbers and complex numbers. These are terms
    > everyone understands including C / C++ programmers. I had a similar
    > question hen I first encountered 'floats and double'. I'd like to
    > believe Real32 and Real64 would suffice, but considering C/C++ has
    > been around for sometime, you chalk it up to 'it is what it is' and
    > move on.


    A "real" type would have to be able to represent irrational numbers -
    which floating point numbers cannot represent, since all floating
    point numbers (except for infinity) are rational.

    > In the end, the OP could always - worse case - typedef the float/
    > double to what he/she considers a more meaningful description. That's
    > the beauty of the language.


    Defining a "real" typedef for float is not going to change the types
    of numbers that a float can represent. So the typedef would not change
    the fact that a float does not represent real numbers, but the "real"
    name could mislead anyone who sees it - into believing that it does.

    Greg
    Greg Herlihy, Mar 25, 2007
    #13
  14. * Greg Herlihy:
    > On Mar 24, 8:58 am, "ma740988" <> wrote:
    >> On Mar 24, 8:43 am, Rolf Magnus <> wrote:
    >>
    >>> Counter question: Is there any particular reason to call it 'real' instead
    >>> of 'float'?

    >> I suspect the OP's thought process reflects what I - perhaps all of us
    >> - was taught in a mathematical sense. In that regard, I'd talk in
    >> terms of integers, real numbers and complex numbers. These are terms
    >> everyone understands including C / C++ programmers. I had a similar
    >> question hen I first encountered 'floats and double'. I'd like to
    >> believe Real32 and Real64 would suffice, but considering C/C++ has
    >> been around for sometime, you chalk it up to 'it is what it is' and
    >> move on.

    >
    > A "real" type would have to be able to represent irrational numbers -
    > which floating point numbers cannot represent, since all floating
    > point numbers (except for infinity) are rational.
    >
    >> In the end, the OP could always - worse case - typedef the float/
    >> double to what he/she considers a more meaningful description. That's
    >> the beauty of the language.

    >
    > Defining a "real" typedef for float is not going to change the types
    > of numbers that a float can represent. So the typedef would not change
    > the fact that a float does not represent real numbers, but the "real"
    > name could mislead anyone who sees it - into believing that it does.


    Well. 'int' is rather misleading too. Come to think of it, is there
    any type name in a programming language that isn't misleading, when one
    thinks of it with mathematical-inspired expectations?

    --
    A: Because it messes up the order in which people normally read text.
    Q: Why is it such a bad thing?
    A: Top-posting.
    Q: What is the most annoying thing on usenet and in e-mail?
    Alf P. Steinbach, Mar 25, 2007
    #14
  15. DirtyHarry

    osmium Guest

    "DirtyHarry" worte:

    > Good day everyone. This sounds like a stupid question, but I became
    > just curious yesterday, and I looked up several textbooks. However, no
    > textbooks on computer language (that I have ) mentioned this. So I am
    > asking to you, gurus...
    >
    > Is there any particular reason to call 'float' instead of 'real'?


    My guess is that it originated with the hardware designers. It seemed
    descriptive so others that came along just adopted it.
    My theory seems to be supported by this link.

    http://www.oars.utk.edu/math_archives/.http/hypermail/historia/apr99/0144.html
    osmium, Mar 25, 2007
    #15
  16. DirtyHarry

    DirtyHarry Guest

    Thanks, everyone... Finally I got out of clouds...
    DirtyHarry, Mar 27, 2007
    #16
  17. DirtyHarry

    SasQ Guest

    Dnia Fri, 23 Mar 2007 21:59:12 -0700, Jim Langston napisa³(a):

    > So if we call a float a real, does that mean we have to
    > call an int a fake?


    unreal :>

    --
    SasQ
    SasQ, Mar 28, 2007
    #17
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