Use Data::Dumper or similar to view the structure of your data. The following should get you close to the output you're looking for. 

#!/usr/bin/env perl

use strict;
use warnings;

[download]
use XML::Fast;
use Template;
use Data::Dumper;

my $xml = <<'XML';
<student>
    <number>24</number>
    <education>bachelors</education>
    <specialization>computers</specialization>
    <address>
        <house_number>128</house_number>
        <street_name>xxxx</street_name>
        <proddutoor/>
    </address>
</student>
<student>
    <number>23</number>
    <education>ph.d.</education>
    <specialization>physics</specialization>
    <address>
        <house_number>12</house_number>
        <street_name>yyyy</street_name>
        <kadapa/>
    </address>
</student>
XML
my $xml_hash = xml2hash $xml;
print Dumper($xml_hash),$/;

my $template = Template->new();
my $filename = 'output.tex';
$template->process(\*DATA, $xml_hash, $filename)
    || die "Template process failed: ", $template->error(), "\n";
system( "pdflatex $filename" );

__DATA__
\documentclass{article}

\title{Roster}
\author{pavani}

\begin{document}
\maketitle

[% FOREACH st IN student %]
Student [% st.number %] is a [% st.specialization %] [% st.education %
+] student and his address is [% st.address.house_number +%] [% st.add
+ress.street_name %].
[% END %]

\end{document}

[download]

As for reading the XML from file you can just slurp it in: 

t.xml =

[download]
<student>
    <number>24</number>
    <education>bachelors</education>
    <specialization>computers</specialization>
    <address>
        <house_number>128</house_number>
        <street_name>xxxx</street_name>
    </address>
</student>
<student>
    <number>23</number>
    <education>ph.d.</education>
    <specialization>physics</specialization>
    <address>
        <house_number>12</house_number>
        <street_name>yyyy</street_name>
    </address>
</student>
<student>
    <number>22</number>
    <education>BS</education>
    <specialization>Biology</specialization>
    <address>
        <house_number>123</house_number>
        <street_name>zzzz</street_name>
    </address>
</student>
<student>
    <number>21</number>
    <education>MS</education>
    <specialization>Agronomy</specialization>
    <address>
        <house_number>321</house_number>
        <street_name>aaaa</street_name>
    </address>
</student>
<student>
    <number>20</number>
    <education>Ph.D</education>
    <specialization>sociology</specialization>
    <address>
        <house_number>333</house_number>
        <street_name>bbbb</street_name>
    </address>
</student>

-- end t.xml

#!/usr/bin/env perl

use strict;
use warnings;

use XML::Fast;
use Template;
use Data::Dumper;

my $xmlfile = 't.xml';
my $xml;
{
  open my $xml_fh, '<', $xmlfile or die "cannot open $xmlfile: $!\n";
  $/ = '';
  $xml = <$xml_fh>;
  close $xml_fh;
}
print Dumper($xml),$/;

my $xml_hash = xml2hash $xml;
print Dumper($xml_hash),$/;

my $template = Template->new();
my $filename = 'output.tex';
$template->process(\*DATA, $xml_hash, $filename)
    || die "Template process failed: ", $template->error(), "\n";
system( "pdflatex $filename" );

__DATA__
\documentclass{article}

\title{Roster}
\author{pavani}

\begin{document}
\maketitle

[% FOREACH st IN student %]
Student [% st.number %] is a [% st.specialization %] [% st.education %
+] student and his address is [% st.address.house_number +%] [% st.add
+ress.street_name %].
[% END %]

\end{document}

[download]

In reply to Re: errors in printing latex template output by keszler
in thread errors in printing latex template output by veerubiji

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