12-12-2019
So your one-liner will not help you if you have more than 3, as it will not take account or will all be in num3, and if someone enters:
1,23,45 you are stuck too...
If you continue with your one-liner read, you will need num4 to be able to check more than 3 numbers were entered, after it does not matter...and you will have to check if you have a valid value in num 1-3 as what is stopping someone to enter "A"?
And while you don't have your 3 numerics in num1-3, you reinitialize your variable to 0 and start again...
---
wisecracker has also shown you what I had in mind and his suggestion solves partially your issue, only this more easy design looks like it is not an option here, as this seems more to be homework to see how smart you are to sort yourself out of this tricky issue when using in such manner the read command...
And so unless you can justify this is not homework and as such should have been posted in the adequate room and following the special rules there I will close this thread
Last edited by vbe; 12-12-2019 at 11:59 AM..
Reason: typos
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RRDp(3) User Contributed Perl Documentation RRDp(3)
NAME
RRDp - Attach RRDtool from within a perl script via a set of pipes;
SYNOPSIS
use RRDp
RRDp::start path to RRDtool executable
RRDp::cmd rrdtool commandline
$answer = RRD::read
$status = RRD::end
$RRDp::user, $RRDp::sys, $RRDp::real, $RRDp::error_mode, $RRDp::error
DESCRIPTION
With this module you can safely communicate with the RRDtool.
After every RRDp::cmd you have to issue an RRDp::read command to get RRDtools answer to your command. The answer is returned as a pointer,
in order to speed things up. If the last command did not return any data, RRDp::read will return an undefined variable.
If you import the PERFORMANCE variables into your namespace, you can access RRDtool's internal performance measurements.
use RRDp
Load the RRDp::pipe module.
RRDp::start path to RRDtool executable
start RRDtool. The argument must be the path to the RRDtool executable
RRDp::cmd rrdtool commandline
pass commands on to RRDtool. Check the RRDtool documentation for more info on the RRDtool commands.
Note: Due to design limitations, RRDp::cmd does not support the "graph -" command - use "graphv -" instead.
$answer = RRDp::read
read RRDtool's response to your command. Note that the $answer variable will only contain a pointer to the returned data. The
reason for this is, that RRDtool can potentially return quite excessive amounts of data and we don't want to copy this around in
memory. So when you want to access the contents of $answer you have to use $$answer which dereferences the variable.
$status = RRDp::end
terminates RRDtool and returns RRDtool's status ...
$RRDp::user, $RRDp::sys, $RRDp::real
these variables will contain totals of the user time, system time and real time as seen by RRDtool. User time is the time RRDtool
is running, System time is the time spend in system calls and real time is the total time RRDtool has been running.
The difference between user + system and real is the time spent waiting for things like the hard disk and new input from the Perl
script.
$RRDp::error_mode and $RRDp::error
If you set the variable $RRDp::error_mode to the value 'catch' before you run RRDp::read a potential ERROR message will not cause
the program to abort but will be returned in this variable. If no error occurs the variable will be empty.
$RRDp::error_mode = 'catch';
RRDp::cmd qw(info file.rrd);
print $RRDp::error if $RRDp::error;
EXAMPLE
use RRDp;
RRDp::start "/usr/local/bin/rrdtool";
RRDp::cmd qw(create demo.rrd --step 100
DS:in:GAUGE:100:U:U
RRA:AVERAGE:0.5:1:10);
$answer = RRDp::read;
print $$answer;
($usertime,$systemtime,$realtime) = ($RRDp::user,$RRDp::sys,$RRDp::real);
SEE ALSO
For more information on how to use RRDtool, check the manpages.
AUTHOR
Tobias Oetiker <tobi@oetiker.ch>
perl v5.16.3 2014-06-10 RRDp(3)