i got nothing in the output file when i give the input xml file for example

_INPUT FILE_
<book>
<a>A
<b>B
<c>C</c>
<e>E</e>
<e>V</e>
</b>
<d>D</d>
</a>
</book>
_OUTPUT FILE_
<?xml version='1.0'?>
<opt></opt>
_EXPECTED OUTPUT_FILE
<?xml version='1.0'?>
<1>A
<2>B
<3>C</3>
<5>E</5>
<5>V</5>
</b>
<4>D</4>
</1>
[download]

Are you sure that is really what you want to do? Your output is not XML (tag names cannot start with a number).

If you use $xhash instead of %xhash on line 56, the program will output something, even if still not the thing you want.