 We don't bite newbies here... much PerlMonks

Re^3: Prime Number Finder

by chith (Initiate)
 on Jan 20, 2013 at 19:45 UTC ( #1014325=note: print w/replies, xml ) Need Help??

in reply to Re^2: Prime Number Finder
in thread Prime Number Finder

this is the actual code which works for windows

#!usr/bin/perl -w use strict; use warnings; my \$o = 2; print "enter upto what number you wish to generate the primes: "; my \$e = <STDIN>; my (\$i,\$j,\$p); my @prime_=(); print "prime numbers are:\n"; for(\$i=\$o; \$i<=\$e; \$i++) { \$p=0; for(\$j=1; \$j<=\$i; \$j++) { if(\$i % \$j== 0) { \$prime_[\$p] = "\$j"; \$p++; } if (\$prime_ == \$i) { print "\$i\t"; } } } print"\n";

Replies are listed 'Best First'.
Re^4: Prime Number Finder
by Anonymous Monk on Sep 17, 2013 at 08:46 UTC
This code is quite fast, since it skips a lot of unnecessary operations
#!/usr/bin/perl use strict; use warnings; use POSIX; my (\$i,\$j,\$h,\$sentinel) = (0,0,0,0); # i>=3 for(\$i=1000000000; \$i<=1000000500; \$i++){ # if \$i is an even number, it can't be a prime if(\$i%2==0){} else{ \$h=POSIX::floor(sqrt(\$i)); \$sentinel=0; # since \$i can't be even -> only divide by odd numbers for(\$j=3; \$j<=\$h; \$j+=2){ if(\$i%\$j==0){ \$sentinel++; # \$i is not a prime, we can get out of the loop \$j=\$h; } } if(\$sentinel==0){ print "\$i \n"; } } }

Create A New User
Node Status?
node history
Node Type: note [id://1014325]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others rifling through the Monastery: (3)
As of 2019-10-13 20:01 GMT
Sections?
Information?
Find Nodes?
Leftovers?
Voting Booth?
In 2019 the site I miss most is:

Results (36 votes). Check out past polls.

Notices?