use strict ;
use warnings ;

my $numClients ;

use Scalar::Util qw(looks_like_number) ;

print "How many Clients are you entering?" ;  
$numClients = <STDIN> ;
chomp($numClients) ;
if ( !looks_like_number($numClients) ) {
   print "   Your input is NOT a numeric\n" ;
   exit(1) ;
}
print "$numClients\n";


__END__
C:\PerlProjects\Monks>perl getposinteger3.pl
How many Clients are you entering?0
0

C:\PerlProjects\Monks>perl getposinteger3.pl
How many Clients are you entering?  -12
  -12

C:\PerlProjects\Monks>perl getposinteger3.pl
How many Clients are you entering? 0005
 0005

C:\PerlProjects\Monks>perl getposinteger3.pl
How many Clients are you entering?14.3
14.3

##</code><code>##

use strict;
use warnings;

my $numClients;

while ( (print "Enter Number of Clients: "), $numClients=<STDIN>,
         $numClients !~ /^\s*(?:[0]*)?[1-9]\d*\s*$/)
{
   print "Your input is NOT a positive integer!\n";
}  

$numClients += 0;  #optional conversion to numeric
print "Number of Clients: $numClients\n";

__END__
C:\PerlProjects\Monks>perl getposinteger2.pl
Enter Number of Clients:     5
Number of Clients: 5

C:\PerlProjects\Monks>perl getposinteger2.pl
Enter Number of Clients:  -23
Your input is NOT a positive integer!
Enter Number of Clients:  2 3
Your input is NOT a positive integer!
Enter Number of Clients:     14.3
Your input is NOT a positive integer!
Enter Number of Clients:   -12 23
Your input is NOT a positive integer!
Enter Number of Clients: 5
Number of Clients: 5

C:\PerlProjects\Monks>perl getposinteger2.pl
Enter Number of Clients:  00003
Number of Clients: 3

##</code><code>##

use strict;
use warnings;

my $numClients;

while ( (print "Enter Number of Clients: "), $numClients=<STDIN>,
         $numClients !~ /^\s*(?:[0]*)?[1-9]\d*\s*$/ or $numClients >=100)
{
   print "Your input is NOT a positive integer less than 100!\n";
}


$numClients += 0;  #optional conversion to numerio
print "Number of Clients: $numClients\n";

__END__

C:\PerlProjects\Monks>perl getposinteger2.pl
Enter Number of Clients: 123
Your input is NOT a positive integer less than 100!
Enter Number of Clients: 5
Number of Clients: 5