XSLT not generating expected output - xslt

Question

Input XML:
<derivatives>
<derivative id="4" name="Audio Content">
<operator id="1" name="Reliance">
<referenceCode code="62033815">
<mobileCircle id="1" name="Maharashtra"/>
</referenceCode>
</operator>
<operator id="22" name="Aircel">
<referenceCode code="811327">
<mobileCircle id="1" name="Maharashtra"/>
</referenceCode>
</operator>
</derivative>
</derivatives>
Expected Output XML:
<hellotune>
<operator>Aircel</operator>
<vcode>811327</vcode>
</hellotune>
Current output (which is wrong):
<hellotune>
<operator>Aircel</operator>
<vcode/>
</hellotune>
XSL (which is not working):
<xsl:if test="derivatives/derivative/operator[#name='Aircel']">
<hellotune>
<operator>Aircel</operator>
<vcode><xsl:value-of select="referenceCode/#code"/></vcode>
</hellotune>
</xsl:if>
Note: Using XSL v1.0. Not mentioned the complete XSL for brevity.

Answer 1

Based on the XSL you provided, it can be presumed that the context node is the root node, but starting from the root node, the path referenceCode/#code does not match anything in your input. Appending derivatives/derivative/operator/ before that path would succeed in finding a referenceCode #code attribute, but it would find the wrong one. Try this push-style approach:
<xsl:template match="/">
<xsl:apply-templates select="derivatives/derivative/operator[#name='Aircel']" />
</xsl:template>
<xsl:template match="operator">
<hellotune>
<operator><xsl:value-of select="#name" /></operator>
<vcode><xsl:value-of select="referenceCode/#code"/></vcode>
</hellotune>
</xsl:template>

Answer 2

The xpath xpression in the element <vcode> is not referring to any node in the input document. The best way to match all the nodes is to use
//
like in your code you can use
//referenceCode/#code
(but this is only for information purpose and using same can't get your result).
you can try this way:
<xsl:template match="/">
<hellotune>
<xsl:for-each select="//operator">
<xsl:if test="./#name='Aircel'">
<operator><xsl:value-of select="#name"/></operator>
<vcode><xsl:value-of select="referenceCode/#code"/></vcode>
</xsl:if>
</xsl:for-each>
</hellotune>
</xsl:template>
Hope this helps :)