Hello, The function sprintf does the rounding automatically. You don't need to add the 0.005.

From the sprintf manual:

f,F  The  double  argument  is  rounded and 
converted to decimal notation in the style -ddd.ddd, 
where the number  of digits after the decimal-point 
character is equal to the precision  specification.  

Doing a small test reveals the same behavior in perl:

#!/usr/bin/perl -w
print `cat $0`;
for $i (1..10){
	my $num = 0;
	for(1..9800*$i){
		$num += 0.0001/$i;
	}
	print "$num = ";
	$num = sprintf("%.4f", $num);
	print "$num\n";
}
0.979999999999908 = 0.9800
0.9799999999999 = 0.9800
0.979999999999902 = 0.9800
0.980000000000962 = 0.9800
0.980000000000699 = 0.9800
0.979999999999897 = 0.9800
0.980000000000605 = 0.9800
0.979999999999383 = 0.9800
0.979999999998648 = 0.9800
0.979999999998175 = 0.9800

Aziz,,,