Thread: is there a log base 2 function?

  1. 05-02-2007 #1
    qubit67
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    is there a log base 2 function?

    I see a log and log10,in math.h, but how do I log base 2 ?
  2. 05-02-2007 #2
    laserlight
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    I believe you can use mathematics, i.e., the change of base formula.

    log_b(a) = log_c(a) / log_c(b)
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way
  3. 05-02-2007 #3
    KONI
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    You can easily calculate a log in base x by doing:

    log (base x) (y) = log (y) / log (x)

    edit: damn ... too slow ...
  4. 05-02-2007 #4
    qubit67
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    thanks, i thought there was a work around
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