How to retrive data from a XML Schema using a C/C++ parser.

I want to build a configuration File in XML Schema.It should look like
<schema>
<applyto>port</applyto>
<type>int</type>
<default>8080</default>
</schema>

What I want is to get the data from the default tag and apply it to the variable in applyto tag..
So when i am using the variable in my program ,it will take the vale from the default tag.
I do not know how to use a parser to parse through the schema and retrive the data.
I need some sample example for better understanding.