diff --git a/src/MSgfile.ml b/src/MSgfile.ml
new file mode 100644
index 0000000..43ddba5
--- /dev/null
+++ b/src/MSgfile.ml
@@ -0,0 +1,99 @@
+open Graph
+open Printf
+open MoneySharing
+
+type path = string
+
+(* Format of text files:
+   % Welcome to MoneySharing, your favorite tool to ease your reimbursements !
+
+   % Please, type the name of all users of your group:
+   u Gaby
+   u Flo
+   u Macha
+
+   % You can now enter your payements as it follows: p userWhoPaid [forWhichUser1; forWhichUser2 ..] amount
+   p Flo [Gaby; Flo; Macha] 11.0
+   p Gaby [Flo] 8.5
+
+*)
+
+
+let write_file path graph l_id=
+
+  (* Open a write-file. *)
+  let ff = open_out path in
+
+  (* Write in this file. *)
+  fprintf ff "%% Here is your MoneySharing graph.\n\n" ;
+
+  (* Write all users *)
+  n_iter_sorted graph (fun id -> fprintf ff "u %s\n" (get_user id l_id)) ;
+  fprintf ff "\n" ;
+
+  fprintf ff "%% Here are the reimbursements to be made.\n\n" ;
+
+  (* Write all arcs *)
+  e_iter graph (fun id1 id2 lbl -> fprintf ff "p %d %d %s\n" (get_user id1 l_id) (get_user id2 l_id) lbl) ;
+
+  fprintf ff "\n%% End of reimbursements\n" ;
+
+  
+
+  close_out ff ;
+  ()
+
+let read_comment graph line l_id=
+  try Scanf.sscanf line " %%" (graph, l_id)
+  with _ ->
+    Printf.printf "Unknown line:\n%s\n%!" line ;
+    failwith "from_file"
+
+(* Reads a line with a user. *)
+let read_user id graph line l_id=
+  try Scanf.sscanf line "u %s" (fun user l_id-> ((init_node graph user id), l_id) )
+  with e ->
+    Printf.printf "Cannot read node in line - %s:\n%s\n%!" (Printexc.to_string e) line ;
+    failwith "from_file"
+
+(* Reads a line with a payement. *)
+let read_payement graph line l_id=
+  try Scanf.sscanf line "p %s %r %f"
+        (fun u l_u label -> ((paiement graph u l_u label), l_id))
+  with e ->
+    Printf.printf "Cannot read arc in line - %s:\n%s\n%!" (Printexc.to_string e) line ;
+    failwith "from_file"
+
+let from_file path =
+
+  let infile = open_in path in
+
+  (* Read all lines until end of file. 
+   * n is the current node counter. *)
+  let rec loop n graph l_id=
+    try
+      let line = input_line infile in
+
+      (* Remove leading and trailing spaces. *)
+      let line = String.trim line in
+
+      let (n2, (graph2, l2)) =
+        (* Ignore empty lines *)
+        if line = "" then (n, (graph, l_id))
+
+        (* The first character of a line determines its content : n or e. *)
+        else match line.[0] with
+          | 'u' -> (n+1, read_node n graph line l_id )
+          | 'p' -> (n, read_arc graph line l_id)
+
+          (* It should be a comment, otherwise we complain. *)
+          | _ -> (n, read_comment graph line l_id)
+      in      
+      loop n2 graph2 l2
+
+    with End_of_file -> (graph, l_id) (* Done *)
+  in
+  let final_graph_lid= loop 0 empty_graph [] in
+
+  close_in infile ;
+  final_graph_lid
\ No newline at end of file
diff --git a/src/MSgfile.mli b/src/MSgfile.mli
new file mode 100644
index 0000000..2a78ae8
--- /dev/null
+++ b/src/MSgfile.mli
@@ -0,0 +1,7 @@
+open Graph
+
+type path = string
+
+val from_file: path -> (string graph, (string,id) list)
+
+val write_file: path -> string graph -> (string,id) list-> unit
diff --git a/src/moneySharing.ml b/src/moneySharing.ml
new file mode 100644
index 0000000..f87cafb
--- /dev/null
+++ b/src/moneySharing.ml
@@ -0,0 +1,28 @@
+open Graph
+
+
+(*fonction qui créé le noeud associé à un utilisateur et rentre la correspondance dans la table des id*)
+let init_node g user id l_id=
+    ((new_node g id), ((user,id)::l_id))
+
+
+(*fonction qui renvoie l'id d'un utilisateur*)   
+let get_id utilisateur l_id= match l_id with   
+    |[]-> raise Not_found
+    |(a,id1)::b-> if a=utlisateur then id1 else get_id utilisateur b
+
+(*fonction qui renvoie le nom correspondant à un id*)   
+let get_user id1 l_id= match l_id with   
+    |[]-> raise Not_found
+    |(nom,a)::b-> if a=id1 then nom else get_user id1 b
+
+(*fonction qui rentre les paiements réalisés*)
+let rec paiement g utilisateur l_utilisateurs montant l_id=
+    let id1=(get_id utilisateur l_id) in
+    match l_utilisateurs with
+    |[]-> (g, l_id)
+    |a::b-> paiement (add_arc g id1 (get_id a l_id) montant) id1 b montant l_id
+
+
+
+
diff --git a/src/moneySharing.mli b/src/moneySharing.mli
new file mode 100644
index 0000000..1a34691
--- /dev/null
+++ b/src/moneySharing.mli
@@ -0,0 +1,9 @@
+open Graph
+
+val paiement: int graphe -> string -> string list -> float -> (string,id) list -> (int graphe, (string,id) list)
+
+val init_node: int graphe -> string ->id -> (string,id) list-> (int graphe, (string,id) list)
+
+val get_id: string -> (string, id) list -> id
+
+val get_user: id -> (string, id) list -> string
\ No newline at end of file