Your program should behave as follows
(assuming the executable is named "DOMcat"):
> DOMcat -p1 test.xml
<?xml version="1.0" encoding="UTF-8"?><book isbn="1-2345-6789-0" year="1994"><title>TCP/IP Illustrated</title><author><last>Stevens</last><first>John</first></author><publisher>Addison-Wesley</publisher><price currency="USD">65.95</price></book>
> DOMcat -p2 test.xml
<?xml version="1.0" encoding="UTF-8"?>
<book isbn="1-2345-6789-0" year="1994">
<title>
TCP/IP Illustrated
</title>
<author>
<last>
Stevens
</last>
<first>
John
</first>
</author>
<publisher>
Addison-Wesley
</publisher>
<price currency="USD">
65.95
</price>
</book>
> DOMcat -p3 test.xml
<?xml version="1.0" encoding="UTF-8"?>
<book isbn="1-2345-6789-0" year="1994">
<title>
TCP/IP Illustrated
</title>
<author>
<last>
Stevens
</last>
<first>
John
</first>
</author>
<publisher>
Addison-Wesley
</publisher>
<price currency="USD">
65.95
</price>
</book>