Question

1. I have the below Perl function to display up to two decimals places. It’s not working when the input value is 2.01, and it gives the output as 2 instead of 2.01. I am not sure why it’s rounding.

Instead of printf I wrote the output to a file, but still it gives me output1 as 2.

    my $ramount = 2.01;
    $ramount = int($ramount*100)/100;
    printf "output1: $ramount";

2. If I have values like .2, .23, .2345, 1,23, 23.1, and 9, what function can I use to pad zeros so that it displays 0.2, 0.23, 0.2345, 1, 23, 23.1, and 9?

Answer 1

I think this sequence will answer your question:

  DB<1> $a=2.01

  DB<2> p $a
2.01
  DB<3> printf "%20.10f\n", $a
        2.0100000000

  DB<4> printf "%20.16f\n", $a
  2.0099999999999998

  DB<5> printf "%20.16f\n", ($a*100)
200.9999999999999716

  DB<6> printf "%20.16f\n", ($a*100)/100
  2.0099999999999998

  DB<7> printf "%20.16f\n", int($a*100)
200.0000000000000000

  DB<8> printf "%20.16f\n", int($a*100)/100
  2.0000000000000000

  DB<9>

Essentially (and this has been answered many times on SO), 2.01 cannot be represented EXACTLY as a floating point number. The closest possible float is, as you see above, 2.009999999999999716…

As to padding, try

printf "%04d", $number

The leading zero in the format tells printf (or sprintf) to left-pad with zero.