Sequence numbering in XSLT 1.0

Question

Hi need some help in XSLT formatting for creating a sequence number for Element tag. Mostly Element tag misses some numbers in sequence and i need to get an output in a sequential format as shown below by adding missing numbers to Element tag in the same sequence of Seat tag.

Any help in this is much appreciated, thanks in advance.

Input

<book>
<Seat>
    <seatNumber>12A</seatNumber>
    <Element>1</Element>
    <Number>1</Number>
</Seat>
<Seat>
    <seatNumber>12B</seatNumber>
    <Element>3</Element>
    <Number>1</Number>
</Seat>
<Seat>
    <seatNumber>12C</seatNumber>
    <Element>4</Element>
    <Number>1</Number>
</Seat>
<Seat>
    <seatNumber>12D</seatNumber>
    <Element>5</Element>
    <Number>1</Number>
</Seat>
<Seat>
    <seatNumber>12E</seatNumber>
    <Element>7</Element>
    <Number>1</Number>
</Seat>
</book>

Output

<book>
<Seat>
    <seatNumber>12A</seatNumber>
    <Element>1</Element>
    <Number>1</Number>
</Seat>
<Seat>
    <seatNumber>12B</seatNumber>
    <Element>2</Element>
    <Number>1</Number>
</Seat>
<Seat>
    <seatNumber>12C</seatNumber>
    <Element>3</Element>
    <Number>1</Number>
</Seat>
<Seat>
    <seatNumber>12D</seatNumber>
    <Element>4</Element>
    <Number>1</Number>
</Seat>
<Seat>
    <seatNumber>12E</seatNumber>
    <Element>5</Element>
    <Number>1</Number>
</Seat>
</book>

Answer 1

Try it this way:

XSLT 1.0

<xsl:stylesheet version="1.0" 
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>
<xsl:strip-space elements="*"/>

<!-- identity transform -->
<xsl:template match="@*|node()">
    <xsl:copy>
        <xsl:apply-templates select="@*|node()"/>
    </xsl:copy>
</xsl:template>

<xsl:template match="Element">
    <xsl:copy>
        <xsl:number count="Seat"/>
    </xsl:copy>
</xsl:template>

</xsl:stylesheet>