I have a struct for a menu system that im trying to modify to reduce memory usage, but i cant figure out a good solution. Basically it looks like this:

struct menu
{
  uint8 str[MAX_STR];        
  uint (*func)( uint8 index );      
  uint index;                     
  menu *prev_ptr;                
  struct menu *submenu_list[MAX_MENUS];     
};

The problem is that all menu items have the submenu_list even if they dont have any submenus. Im trying to find out a way to have it more dynamically allocated instead of an array of always length MAX_MENUS. Is there an obvious solution here or will i need to revamp the whole menu system

One idea was to have a single pointer in the menu struct pointing to an array of the submenus, but i haven’t gotten it to work.

struct menu
{
  uint8 str[MAX_STR];        
  uint (*func)( uint8 index );      
  uint index;                     
  menu *prev_ptr;                
  struct menu *submenu_list;     
};

and then when initializing a menu like this

menu *submenus_main[] =       { &submenu1, &submenu2, &submenu3, &submenu4, &submenu5, 0};
static menu main_menu =       { "Main Menu", 0, 0, 0, &submenus_main };