Q:

What will be output if I print local time return values?

I printed the localtime return values without storing that into one variable, it is display some digits I don't know what is that, but if we use that return value in localtime and store that into scalar variable it is displaying some date format.
for example 
print localtime,"\n";

its print output 
713156411531250

then I give that output to arguments of localtime like 
$time=localtime(713156411531250);
print "$time\n";

Output:
Sat Jan 14 16:37:30 22600997

A:

Perl in general, and localtime specifically is magic - it knows in what context it's being used. 
So you can use things like wantarray() within a sub to detect whether the caller is expecting multiple results. 
localtime is much the same.
If you 'use' it in a LIST context, it returns a list of values: 
my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) =
                                            localtime(time);

You are effectively doing this by 'just' printing it. 
E.g.
print scalar localtime,"\n";
print join ( " ", localtime );

Gives:
Fri May  8 11:20:15 2015
15 20 11 8 4 115 5 127 1

