using references within a function

[rupertInAust]

I tried to create a function that would run an output
based on the ref() function. it works in the main part,
but when I place the routine in a sub, the referencing
stuffs up. any clues? i've included all the code so you
can run it in your own IDE's if it helps. thanks heaps.


the output is;

defined:1
it's a hash ref:HASH(0x14d0e4)


the plan was that they print the same
(the #1 "defined:1" is not what I want,
#2 for both is what i'm aiming for )
and they don't. anybody know what i'm doing wrong?

[tt]
use warnings;
use strict;


my %coins = ( "Quarter" , '25', "Dime" , '10' , "Nickel", '05');
my $ref = \%coins;


detAndPnt($ref);


if (ref($ref) eq 'HASH'){
print "it's a hash ref:";
print $ref."\n";
}
elsif (ref($ref) eq 'ARRAY'){
print "it's a array ref:";
print $ref."\n";
}
else{
if(defined($ref)){
print "defined:";
print $ref."\n";
}
else{
print "it's undef\n";
}
}


#-sub routine--------------------------------


sub detAndPnt{
if (ref(@_) eq 'HASH'){
print "it's a hash ref:";
print @_."\n";
}
elsif (ref(@_) eq 'ARRAY'){
print "it's a array ref:";
print @_."\n";
}
else{
if(defined(@_)){
print "defined:";
print @_."\n";
}
else{
print "it's undef\n";
}
}
}
[/tt]

 

[stevexff]

Don't you need to be checking @_[0] rather than just @_ in your sub?

Steve

[small]"Every program can be reduced by one instruction, and every program has at least one bug. Therefore, any program can be reduced to one instruction which doesn't work." (Object:erlDesignPatterns)[/small]

 

[rupertInAust]

You are spot on. replaced
[tt]@_[/tt] with [tt]$_[0][/tt]
and worked perfectly. thanks so much.

 

[tchatzi]

this

my $ref = \%coins;
detAndPnt($ref);

means that you are passing to the subroutine a refernce to a hash or a reference to a whatever.
So in your subroutine you must check if what you take in is a reference to something .
so notice the red spots.

use warnings;
   use strict;


   my %coins = ( "Quarter" , '25', "Dime" , '10' , "Nickel", '05');
   my $ref = \%coins;


   detAndPnt($ref);


   if (ref($ref) eq 'HASH'){
      print "it's a hash ref:";
      print $ref."\n";
   }
   elsif (ref($ref) eq 'ARRAY'){
      print "it's a array ref:";
      print $ref."\n";
   }
   else{
      if(defined($ref)){
         print "defined:";
         print $ref."\n";
      }
      else{
         print "it's undef\n";
      }
   }


   #-sub routine--------------------------------


   sub detAndPnt{
      [red]my $foo = shift;[/red]
      if (ref([red]$foo[/red]) eq 'HASH'){
         print "it's a hash ref:";
         print [red]$foo[/red]."\n";
      }
      elsif (ref([red]$foo[/red]) eq 'ARRAY'){
         print "it's a array ref:";
         print [red]$foo[/red]."\n";
      }
      else{
         if(defined([red]$foo[/red])){
            print "defined:";
            print [red]$foo[/red]."\n";
         }
         else{
            print "it's undef\n";
         }
      }
   }

``The wise man doesn't give the right answers,
he poses the right questions.''
TIMTOWTDI

 

[rupertInAust]

I haven't used shift much but that's a good application for it. Thanks again.