# to the nth power
Peter Knight
prk at planet.bt.co.uk
Sat Nov 3 02:24:43 AEST 1990
CJH101 at psuvm.psu.edu (Carl J. Hixon) writes:
>I appologize for bothering you computer wizards with such an elementary
>question but, I'm floundering. Why am I unable to find an opperator which
>raises a number to a power. (The fortran equivalent of x**n) Is there such
>an opporator or do I need to write my own function? It seems like a terrible
>oversite to me that such a common operation was overlooked.
>Any help would be greatly appreciated! I'm not sure I could even write the
>function, I'm currently writing my first C program ever...
>Thankyou,
>Carl
The likely offered solutions in C, involving ln()/exp() or the pow() functions
are not going to be a capable as Fortran's x**n. These functions cannot cope
with Fortran legal operations like (-1e6)**10. Usually, you will have to
cope with the sign yourself. The other 'gotcha' you are going to encounter
is that doubles rather than floats have a greater range of values (!), ie
double d;
float f;
d=1e300;
f=d; /* This is a error on 99% of machines */
Peter Knight
BT Research
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