Function_Tree

 39 void foreach(itemt const *root, void (*func)(int)){
 40         itemt const *cur = root;
 41         func(cur->value);
 42         if (cur->left){
 43                 foreach(cur->left, func);
 44         }
 45         if (cur->right){
 46                 foreach(cur->right, func);
 47         }
 48 }
 49
 50 itemt* map(itemt const *root, int (*func)(int)){
 51           itemt const *cur = root;
 52           itemt  *new_list = tree_new(func(cur->value));
 53           if (cur->left){
 54                   new_list->left = map(cur->left, func);
 55                  }
 56           if (cur->right){
 57                   new_list->right = map(cur->right, func);
 58           }
 59           return new_list;
 60   }
 61
 62 int foldl(itemt const *root, int (*func)(int, int), int acc){
 63         itemt const *cur = root;
 64         if (cur->left){
 65                 acc = foldl(cur->left, func, acc);
 66         }
 67         if (cur->right){
 68                 acc = foldl(cur->right, func, acc);
 69         }
 70         acc = func(cur->value, acc);
 71         return acc;
 72 }