In rashida.par's Recursive function to find X to the power n (http://www.go4expert.com/showthread.php?t=9307) I see that she intelligently used recursion to find the power of x to n. So, I was wondering whether we can do this iteratively also, I always do that - trying to find a iterative solution to a recursive one. Being more of a Perl programmer than C, I wrote my code in Perl - can be understood by any programmer. I also benchmarked the recursive function to the iterative version. The Iterative Solution Code: sub power_iterative { my ($x,$n) = @_; ## take in parameters my $result = 1; while($n--) { $result *= $x; } return $result; } Test run of the code: Code: printf("\n %.4f to the power of % d is %.4f",$x,$n,power_iterative($x,$n)); Code: [pradeep@go4expert perl_test]$ perl power_iterative.pl 4.0000 to the power of 10 is 1048576.0000 Benchmarking I also benchmarked the recursive function to the iterative version to see which one performs better. Code: use Benchmark; sub power_iterative { my ($x,$n) = @_; ## take in parameters my $result = 1; while($n--) { $result *= $x; } return $result; } sub power_recursive { my ($x,$n) = @_; ## take in parameters if ($x==0) { return 0; } elsif($n==0) { return 1; } elsif ($n>0) { return( $x* power_recursive($x,$n-1)); } else { return ((1/$x)*power_recursive($x,$n+1)); } } my ($x,$n) = (4,10); timethese(400000,{ 'iterative'=> sub{my $power = power_iterative($x,$n);}, 'recursive'=> sub{my $power = power_recursive($x,$n);}}); Result: Code: [pradeep@go4expert perl_test]$ perl power_iterative.pl Benchmark: timing 400000 iterations of iterative, recursive... iterative: 2 wallclock secs ( 1.28 usr + 0.00 sys = 1.28 CPU) @ 312500.00/s (n=400000) recursive: 6 wallclock secs ( 5.90 usr + 0.00 sys = 5.90 CPU) @ 67796.61/s (n=400000) As we see here, the iterative version performs much better than the recursive one, the reason being the recursive version need more memory for function call stacks etc. I hope this was helpful to you all.

As was evident from the Recursive implementation, there was tail recursion, which is both redundant & inefficient. Tail recursion must always be replaced with a more efficient, easier to comprehend iterative counter-part, as you have done here. Only, you have done it in Perl - a language which I do not know much about - so I got to learn the basics of a new language as well! Regards, Rajiv