diff --git a/treeh.c b/treeh.c
index f4975b4..489ea31 100644
--- a/treeh.c
+++ b/treeh.c
@@ -7,16 +7,18 @@ tree make_empty_tree(){
 node* make_empty_node(){
   node*n=malloc(sizeof(node));
   n->letter='\0';
-  n->isEnd=false;
+  n->isEnd=0;
   for(int i=0;i<NBCHAR;i++)
     n->next[i]=make_empty_tree();
+	return n;
 }
-node* make_node(char l,bool end){
+node* make_node(char l,int end){
   node*n=malloc(sizeof(node));
   n->letter=l;
   n->isEnd=end;
   for(int i=0;i<NBCHAR;i++)
     n->next[i]=make_empty_tree();
+	return n;
 }
 void delete_tree(tree t){
   if(is_empty(t))return;
@@ -30,10 +32,10 @@ void delete_tree(tree t){
 
 
 //Casual functions
-bool is_empty(tree t){
+bool is_empty(const tree t){
   return t==NULL;
 }
-bool is_followed(tree t){
+bool is_followed(const tree t){
   int i;
   for(i=0;i<NBCHAR;i++){
     if(t->next[i]!=NULL)
@@ -42,50 +44,52 @@ bool is_followed(tree t){
   return false;
 }
 
-bool is_end(tree t){return t->isEnd%2;}
-bool ends_with_apostrophe(tree t){return (t->isEnd/4)%2;}
+//functions is_end
+bool is_end(const tree t){return t->isEnd & 1;}
+bool ends_with_apostrophe(const tree t){return t->isEnd & 2;}
  
-bool is_common_end(tree t){return !(t->isEnd/4);}
-bool is_proper_end(tree t){return (t->isEnd/4)%2;}
-bool is_acronyme_end(tree t){return t->isEnd/8;}
+bool is_common_end(const tree t){return !(t->isEnd & 12);}
+bool is_proper_end(const tree t){return t->isEnd & 4;}
+bool is_acronyme_end(const tree t){return t->isEnd & 8;}
+
 int hash(char c){
   //needs to check c wether isalpha
   return c%32-1;
 }
-bool is_proper_end(tree);//if true 1st letter is upper ;//if true all letters are lower
 
 
 
 //loading functions
-bool addto_tree(tree t,string s){
-  //recursive, need to check all letter in s are alpha or '\'s'
+bool addto_tree(tree t,const string s,char endKind){
+  //recursive, need to check all letter in s are alpha or "\'s"
   //return wether s is already in t or not
   bool ret;
   if(s[0]=='\0'){
     ret=is_end(t);
-    t->isEnd=true;
+    t->isEnd=t->isEnd|endKind;
     return ret;
   }
   if(s[0]=='\''){
-    
+    ret=ends_with_apostrophe(t);
+		t->isEnd=t->isEnd|endKind;
+		return ret;
   }
   if(t->next[hash(s[0])]==NULL){
-    t->next[hash(s[0])]=make_node(s[0],false);
-    addto_tree2(t->next[hash(s[0])],s+1);
+    t->next[hash(s[0])]=make_node(s[0],0);
+    addto_tree2(t->next[hash(s[0])],s+1,endKind);
     return false;
   }
   else    
-    addto_tree(t->next[hash(s[0])],s+1,isIn);
+    return addto_tree(t->next[hash(s[0])],s+1,endKind);
 }
-void addto_tree2(tree t,string s){
+void addto_tree2(tree t,const string s,char endKind){
   //faster than addto_tree
   //used when it is known the word is not yet in dictionnary
-  if(s[0]=='\0'){
-    t->isEnd=true;
+  if(s[0]=='\0' || s[0]=='\''){
+    t->isEnd=endKind;
     return;
   }
-  if(s[0]=='\'')
-  t->next[hash(s[0])]=make_node(s[0],false);
-  addto_tree2(t->next[hash(s[0])],s+1);
+  t->next[hash(s[0])]=make_node(s[0],0);
+  addto_tree2(t->next[hash(s[0])],s+1,endKind);
 }
 
diff --git a/treeh.h b/treeh.h
index d42ea04..551ba9a 100644
--- a/treeh.h
+++ b/treeh.h
@@ -8,11 +8,11 @@
 
 #define NBCHAR 26 //A-Z
 
-
+typedef char *string,byte;
 typedef struct _node node, *tree;
 struct _node{
   char letter;
-  char isEnd;
+  byte isEnd;
   //0 no,1 yes,+2 if ends with 's
   //+4if proper, +8if allUpper 
   node* next[NBCHAR];
@@ -20,23 +20,24 @@ struct _node{
 
 tree make_empty_tree();//create a null node*
 node* make_empty_node();//malloc a node and initialize it
-node* make_node(char,bool);//id
+node* make_node(char,byte);//id
 void delete_tree(tree);//free(tree) and delete tree on all t->next
 
-bool is_empty(tree);//==NULL
-bool is_followed(tree);//if true tree has following letters
+bool is_empty(const tree);//==NULL
+bool is_followed(const tree);//if true tree has following letters
 
-bool is_end(tree);//if true word can end here
-bool is_proper_end(tree);//if true 1st letter is upper  
-bool is_common_end(tree);//if true all letters are lower
-bool is_acronyme_end(tree);//if true all letters are upper
-bool ends_with_apostrophe(tree);//if true word can be word's
+bool is_end(const tree);//if true word can end here
+bool ends_with_apostrophe(const tree);//if true word can be word's
+bool is_common_end(const tree);//if true all letters are lower
+bool is_proper_end(const tree);//if true 1st letter is upper  
+bool is_acronyme_end(const tree);//if true all letters are upper
 
 int hash(char);//need to check if isalpha
 
 //recursive can only be called in a dico instance
-void addto_tree(tree,string,int);
-void addto_tree2(tree,string);
+//
+bool addto_tree(tree,const string,byte);
+void addto_tree2(tree,const string,byte);
 
 
 #endif //TREEH_H
--
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