Sort XML elements in predetermined order using XSLT

Question

I have to following XML:

Answer 1

Now I want to sort the elements in a predefined way (first b, then a, then c).

Here's one way:

<xsl:stylesheet version="2.0" 
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" version="1.0" encoding="utf-8" indent="yes"/>

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

<xsl:template match="/root">
    <xsl:copy>
       <xsl:apply-templates select="b"/>
       <xsl:apply-templates select="a"/>
       <xsl:apply-templates select="c"/>
    </xsl:copy>
</xsl:template>

</xsl:stylesheet>

Here's another:

XSLT 2.0

<xsl:stylesheet version="2.0" 
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" version="1.0" encoding="utf-8" indent="yes"/>

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

<xsl:template match="/root">
    <xsl:copy>
        <xsl:apply-templates select="*">
            <xsl:sort select="index-of(('b', 'a', 'c'), name())" />
        </xsl:apply-templates>
    </xsl:copy>
</xsl:template>

</xsl:stylesheet>