#!/usr/bin/perl

# restrict the number of digits after the decimal point
sub restrict_num_decimal_digits
{
  my $num=shift;#the number to work on
  my $digs_to_cut=shift;# the number of digits after 
		  	    # the decimal point to cut 
		#(eg: $digs_to_cut=3 will leave 
		# two digits after the decimal point)

  if ($num=~/\d+\.(\d){$digs_to_cut,}/)
  {
    # there are $digs_to_cut or 
    # more digits after the decimal point
    $num=sprintf("%.".($digs_to_cut-1)."f", $num);
  }
  return $num;
}

my $a_number="11.299999999999";
#cut the third digit after the decimal point 
print "\nThe result for \"$a_number\",cut 3 digits is: ";
print &restrict_num_decimal_digits($a_number,3);

$a_number="12.345"; 
#first cut the third digit after the decimal point 
#then cut the second
print "\nThe result for \"$a_number\",cut 3 digits is: ";
print &restrict_num_decimal_digits($a_number,3);
print "\nThe result for \"$a_number\",cut 2 digits is: ";
print &restrict_num_decimal_digits($a_number,2);

$a_number="13.34";
# cut the third digit after the decimal point 
print "\nThe result for \"$a_number\",cut 3 digits is: ";
print &restrict_num_decimal_digits($a_number,3);

$a_number="14.3";
# cut the third digit after the decimal point 
print "\nThe result for \"$a_number\",cut 3 digits is: ";
print &restrict_num_decimal_digits($a_number,3);

$a_number="15";
# cut the third digit after the decimal point 
print "\nThe result for \"$a_number\",cut 3 digits is: ";
print &restrict_num_decimal_digits($a_number,3);