[564596] Added helper method for simplyfing struct generation

Added proteted member for accessing struct members. This makes the
generated struct code nicer to read and easier to generate.

Bug: https://bugs.eclipse.org/bugs/show_bug.cgi?id=564596
Change-Id: I719d2ab083d672f444b37a46aeb700140a5cab9a
diff --git a/src/core/datatypes/forte_struct.h b/src/core/datatypes/forte_struct.h
index 120443f..0ac5d7d 100644
--- a/src/core/datatypes/forte_struct.h
+++ b/src/core/datatypes/forte_struct.h
@@ -113,7 +113,6 @@
     const CIEC_ANY *getMembers() const{
       return (0 != getSpecs()) ? getSpecs()->mMembers : static_cast<CIEC_ANY *>(0);
     }
-
     /*! \brief Get the struct's member var with the given name id
      *
      * \param pa_unMemberNameId the string id of the member name
@@ -124,6 +123,17 @@
     virtual size_t getToStringBufferSize() const;
 
   protected:
+    /*! \brief helper method for accessing a member by index
+     *
+     * Mainly used for the generated accessor-functions.
+     * Therefore the index is not range checked!
+     *
+     * \param paMemberIndex index into the member array
+     * \return pointer to the member var
+     */
+    CIEC_ANY* getMember(size_t paMemberIndex){
+      return &getMembers()[paMemberIndex];
+    }
 
     enum EASN1Tags{
       e_UNIVERSAL = 0, e_APPLICATION = 64, e_CONTEXT = 128, e_PRIVATE = 192