Header in tableview with search bar

Hello,

I tested the tutorial about searchbar in table view (Candy search : UISearchController Tutorial: Getting Started)

I would know how to add a titleForHeaderInSection for classify by alphabitcal order the candies ?

titleForHeaderInSection = C
name: Chocolate Bar and category : chocolate.
titleForHeaderInSection = D
name: Dark Chocolate and category : Chocolate.
etc.

I have a table view with struct like this :

 `struct Lexiquefrsa {
         let sectionLetter : String!
         let sectionFRSAfr : [String]!
        let sectionFRSAsa : [String]!
       }

      var lexiquefrsaArray = [Lexiquefrsa]()

and in my super.viewDidLoad() :

 lexiquefrsaArray = [
        Lexiquefrsa(sectionLetter: "A", sectionFRSAfr: ["aa, "ab",... ], sectionFRSAsa: ["aa", "ab", ... ]),
        Lexiquefrsa(sectionLetter: "B", sectionFRSAfr: ["ba", "bb", ... ], sectionFRSAsa: ["ba", "bb",  ... ]), ... etc.

I tried several solutions but can not find the right method …

Can you help me ?