Run code with elevated privileges in SharePoint

“The RWEP method enables you to supply a delegate that runs a subset of code in the context 

of an account with higher privileges than the current user”

Exact Definition:

If the user has the required level of permissions to do a certain action like delete,update,move to then we need to use the Run with Elevated Privileges method for access or use it.

How To Use :

private void CustomFunction()

{

            // Non-Elevated Permission Code Goes Here

            SPSecurity.RunWithElevatedPrivileges(delegate()

            {

                         SPSite site = SPContext.Current.Site;   

                         SPWeb web = SPContext.Current.Web;

                          //New SPSite object.

                         using (SPSite newsite = new SPSite(Site.ID))

                         {

                                      //New SPWeb object.

                                     using (SPWeb newWeb = newSite.OpenWeb(web.ID))

                                     {

                                    //Do things by assuming the permission of the "system account".

                                      }

                        }

            });  // Note the Brackets used while creating delegate

}

Example:

private void CustomFunction()
{
      SPSite site = SPContext.Current.Site;
      SPWeb web = SPContext.Current.Web;

      SPSecurity.RunWithElevatedPrivileges(delegate()
      {
            using (SPSite newSite = new SPSite(site.ID))
            {
                  using (SPWeb newWeb = newSite.OpenWeb(web.ID))
                  {
                        list = newWeb.Lists["ElevatedListTest"];
                        SPListItem newItem = list.Items.Add();
                       
                        // Do stuff to create the list item
 
                        newWeb.AllowUnsafeUpdates = true;
                        newItem["Title"] = "Testing Title";
                        newItem.Update();
                                          list.Update();
                        newWeb.AllowUnsafeUpdates = false;
                  }
            }
       });
}

                 Or 

Among the two approaches which one is preferred with run with elevated privileges?

First Approach:

SPSecurity.RunWithElevatedPrivileges(delegate()
                {
                    using (SPSite curSite = new SPSite(SPContext.Current.Site.ID))
                    {
                        using (SPWeb web = curSite.OpenWeb(SPContext.Current.Web.ID))
                        {
                            try
                            {
                                web.AllowUnsafeUpdates = true;
                                \\ do your stuff
                            }
                            catch (Exception e)
                            {

                            }
                            finally
                            {
                                web.AllowUnsafeUpdates = false;
                                web.Dispose();
                            }
                        }
                    }
                });

Second Approach:

SPSite oSite = SPContext.Current.Site;
SPWeb oWeb = SPContext.Current.Web;
SPSecurity.RunWithElevatedPrivileges(delegate()
                {
                    using (SPSite curSite = new SPSite(oSite.ID))
                    {
                        using (SPWeb web = curSite.OpenWeb(oWeb.ID))
                        {
                            try
                            {
                                web.AllowUnsafeUpdates = true;
                                \\ do your stuff
                            }
                            catch (Exception e)
                            {

                            }
                            finally
                            {
                                web.AllowUnsafeUpdates = false;
                                web.Dispose();
                                oWeb.Dispose();
                                oSite.Dispose();
                            }
                        }
                    }
                });