Inheritance in perl is showing a error in my case

Question

I have two perl modules onee.pm and two.pm and one perl script.Following is one.pm

 package one;
sub foo
{
 print "this is one\n";
}
sub goo
{
 print "This is two\n";
}
1;

two.pm

package two;
use one;
@ISA=(one);
sub hoo
{
  print "this is three \n";
}
1;

inherit.pl

use two;
foo();

when i execute inherit.pl am getting following error.

 Undefined subroutine &main::foo called at inherit.pl line 2.

Answer 1

Inheritance works on objects. What you're trying to do is importing, not inherit. I've outlined both an example of inheritance and importing below.

Inheritance:

One.pm:

package One;

sub foo {
    print "this is one\n";
}
1;

Two.pm:

package Two;

# Note the use of 'use base ...;'. That means that we'll inherit 
# all functions from the package we're calling it on. We can override
# any inherited methods by re-defining them if we need/want

use base 'One';

sub new {
    return bless {}, shift;
}
1;

inherit.pl:

use warnings;
use strict;

use Two;

my $obj = Two->new;
$obj->foo;

Importing:

One.pm:

package One;

use Exporter qw(import);
our @EXPORT_OK = qw(foo); # allow user to import the 'foo' function if desired

sub foo {
    print "this is one\n";
}
1;

Two.pm:

package Two;
use One qw(foo); # import foo() from One

use Exporter qw(import);
our @EXPORT_OK = qw(foo); # re-export it so users of Two can import it

1;

import.pl:

use warnings;
use strict;

use Two qw(foo);

foo();

Note that in the next Perl Release (5.26.0), @INC will not include the current working directory by default, so to use One; or use Two; if those module files are in the local directory, you'll have to add use lib '.'; or unshift @INC, '.'; or the like.