Exponentiation in C (was: How not to write a loop)

[Bill Gibbons]

In article <4778 at haddock.ISC.COM> karl at haddock.ima.isc.com (Karl Heuer) writes:
>In article <808 at l.cc.purdue.edu> cik at l.cc.purdue.edu (Herman Rubin) writes:
>>In article <12784 at apple.Apple.COM>, bgibbons at Apple.COM (Bill Gibbons) writes:
>>>... raising a floating-point value to an integer (typed as integer) power is
>>>always done with repeated multiplies (in about log2(exponent) time),
>That's a strange comment to be posting to a C newsgroup.

Actually, I meant this from an algorithmic point of view: if the implementor
knows that the exponent is an integer (without checking, e.g. it was typed
that way) the library code should use repeated multiplies.  This is trivial to
do in C++ by overloading pow().  In C, you have to name the library routine
something else, of course.  Or, as has been noted, change the language.

Bill Gibbons
bgibbons at apple.apple.com (contractor)