Thanks Alot for explanation with example and your worked perfectly i have one more Q...my $padacntnum =sprintf("%017d",$bgl) this is going to round off every number ??

It probably is not possible to predict the results in every case. Consider these two runs of your function. Only the second replicates your original problem.

use strict;
use warnings;
no warnings 'experimental::signatures';
use feature 'signatures';

sub amnt($amn)
{
my $amount=$_[0];
print "$amount i m checking amount before padding,\n";
my $padamnt = sprintf("%016d",$amount);
print "$padamnt i m checking amount after padding,\n";
 return $padamnt;
}

print "EXACT integer\n";
amnt(488715);

print "\n\nNot quite an integer\n";
amnt(488715 - 4e-10);
[download]

OUTPUT:

EXACT integer
488715 i m checking amount before padding,
0000000000488715 i m checking amount after padding,


Not quite an integer
488715 i m checking amount before padding,
0000000000488714 i m checking amount after padding,
[download]

Bill