Thread: Order of Operations

  1. #1
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    Order of Operations

    When evaluating order of operations like a problem x = a + (b - c) / (d - e * f). Do you evaluate left to right or right to left? Thanks for your time guys.

    -Will

  2. #2
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    as far as I know it is always left to right for all infix notation

  3. #3
    Programming Sex-God Polymorphic OOP's Avatar
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    Originally posted by samps005
    as far as I know it is always left to right for all infix notation
    It's actually not defined, believe it or not!

    Only a few operators guarantee order, which include

    ||
    &&

    so that you can be certain of the short-circut evaluation.

    with addition, subtraction, etc. it's up to the compiler to choose order.

    so in

    a + (b - c) / (d - e * f).

    The compiler can do

    b - c

    first, or it can do

    ( d - e * f )

    first. It's not defined by the standard.

  4. #4
    CS Author and Instructor
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    I think you confused him... anyway it is on page 200 of the The C Programming Lang book (K & R).
    Mr. C: Author and Instructor

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