So, I wanted to understand the printf command and how to manipulate the formatting of a number (yes I am that new to this), namely how to insert a variable into %.f it would seem %.{$var}f does the trick.

And In this small script I thought I had it worked out

If I enter 1.111111111111111111111111111111 (1 with 30 1s after the decimal point) as an experimental value, when asked 'How many digits would you like after the decimal point ? ' if I answer 2 I get 1.11 as expected.

If I answer 10 I get 1.1111111111 as I would expect.

However if I answer 20 I get 1.11111111111111116045 (?)

And if I answer 30 I get 1.111111111111111160454356650007 (?)

Can someone tell me why please.


#! /usr/bin/perl -w

# experiment with printf

use strict;

my $num = 0;
my $dig = 0;

print 'Input a number :';
chomp( $num = <STDIN> );
print 'How many digits would you like after the decimal point ? ';
chomp( $dig = <STDIN> );
print "\n";
print 'Original number was ';
print "$num \n";
printf("And to $dig, points is ");
printf( "%.${dig}f", $num );
print "\n\n";

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In reply to Why do I get random numbers? by Cleggy

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