# to the nth power
Rory Jacobs
rory at maccs.dcss.mcmaster.ca
Fri Nov 2 12:58:25 AEST 1990
In article <1990Nov1.232830.17131 at NCoast.ORG> you write:
>In article <9750 at helios.TAMU.EDU> randy at cs.tamu.edu (Randy Hutson) writes:
>>In article <15984 at mentor.cc.purdue.edu-> edgincd2 at mentor.cc.purdue.edu (Chris Edgington *Computer Science Major*) writes:
>>->In article <90305.005050CJH101 at psuvm.psu.edu->, CJH101 at psuvm.psu.edu (Carl J. Hixon) writes:
[
Lots of methods for computing a raised to the power n deleted
]
Oh well, I *mailed* everything said in the above articles to the original
poster. But the last one (iterative computation of a^n) makes me post the
following version:
int power2 (x,n)
/* note that x, p, sqp if made type double this would allow
* x^n for real numbers x and integers n. This just does integers
* x raised to the intger powers
*/
int x;
int n;
{
int p = 1.0;
int sqp = x;
int i=n;
while (i>0) {
if ((i % 2) == 1) p *= sqp;
sqp *= sqp;
i = i / 2;
}
return(p);
}
This calculates x^n and run in O(log2 n) time...
Rory "Bug Slayer" Jacobs
rory at maccs.dcss.mcmaster.ca
More information about the Comp.lang.c
mailing list