title: Using same variable in two functions
body: <p>I have two functions <code>read()</code> and <code>write()</code>. I read a file in the <code>read()</code> function and store a line in the header in a variable. Now i want the <code>write()</code> function to write that same line to a new file. But how can i use the same variable or information from the other function? What is the way to do this?</p>
  
  <p>Here is some info about the code:</p>
  
  <p>After including necessary files, it says this</p>
  
  <pre><code>HX_INIT_CLASS(HxCluster,HxVertexSet);
  </code></pre>
  
  <p>The name of the class is HxCluster and it would be great if someone can tell me why it is not like we define classes in the simple way: <code>class class_name {};</code></p>
  
  <p>The I have many functions out of which two are <code>read()</code> and <code>write()</code>. They both take one argument only which is the file to be read and the file to be written to in the respective cases. I don't know if writing the code for that will help here. </p>