title: How to call a helper class magento
body: <p>I am trying to call a helper class in magento but stuck with an error message from magento.</p>
  
  <p>The helper class is located at </p>
  
  <blockquote>
    <p>app/code/core/Mage/Catalog/Helper/Product/Compare.php</p>
  </blockquote>
  
  <p>The class name is </p>
  
  <pre><code>class Mage_Catalog_Helper_Product_Compare extends Mage_Core_Helper_Url
  </code></pre>
  
  <p>I tried the below call</p>
  
  <pre><code>$helper=Mage::helper('catalog_product_compare');
  </code></pre>
  
  <p>Error message I got</p>
  
  <blockquote>
    <p>Fatal error: Class 'Mage_Catalog_Product_Compare_Helper_Data' not
    found in C:\xampp\htdocs</p>
  </blockquote>
  
  <p>How can i call this helper class?</p>