hello guys. I want guidance how I can create an menu system using structs.
I am just mediocre in C. I have created some menu system for my projects using state-machine but it gets quite messy if there are a lot of menus and sub menus.
I have also looked for some examples online where they are using structs but it just goes from top of my head.
so can anyone guide me here or point to any good resource explaining it
thank you 
there are many libraries, here is a couple google hits
I also found libraries but I dont want to use them. Want to learn to create by myself.
IF what you find goes over the top of your head, then you are NOT starting with the basics and build from there.
You have to handle multiple aspects. First comes the menu tree structure. Next is display of the menu and navigation through the menu entries. The kind and size of the display is important. E.g. small (LCD) displays require menu scrolling.
I'd implement the independent aspects in base classes which then can be implemented depending on the screen type and input methods. Not easy without an understanding of OOP (Object Oriented Programming).
hmmm
Good project for learning! Take your time.
i developed a table driven menu system that was focused on setting parameters that affected behavior and allowed entry of strings and numeric values using buttons.
#ifndef MENU_H
# define MENU_H
# define Clear "\e[2J\e[0;0H"
# define Normal "\e[0m"
# define Bold "\e[1m"
# define Blink "\e[5m"
# define Red "\e[31m"
# define Yellow "\e[33m"
# define Blue "\e[34m"
#define MAX_DIGIT 5
// button and display function pointers
typedef struct {
void (*menu) (void *);
void (*sel) (void *);
void (*up) (void *);
void (*dn) (void *);
void (*disp) (void *);
} Func_t;
// parameter descripton
typedef struct {
const char *text;
int *param;
int min;
int max;
void *p;
Func_t func;
} P_t;
// parameter types
typedef enum {
T_NULL,
T_NONE,
T_MENU,
T_PARAM,
T_STR,
T_LIST,
} T_t;
inline const char *
menuType (T_t t)
{
switch (t) {
case T_NULL:
return "T_NULL";
break;
case T_NONE:
return "T_NONE";
break;
case T_MENU:
return "T_MENU";
break;
case T_PARAM:
return "T_PARAM";
break;
case T_STR:
return "T_STR";
break;
case T_LIST:
return "T_LIST";
break;
default:
return "unknown";
break;
}
}
// menu description
typedef struct {
const char *text;
const char *text2;
T_t type;
void *ptr;
int *pParam;
} Menu_t;
// menu stimuli
typedef enum {
M_NULL,
M_MENU,
M_SEL,
M_UP,
M_DN,
M_LAST
} MenuStim_t;
// -------------------------------------------------------------------
// menu functions
void __ (void *); // null function
void sel (void *); // select list item
void sft (void *); // shift digit to edit next digit to the right
void sfA (void *); // shift digit to right, not past NULL
void deA (void *); // decrement value of a character (' ' to '~')
void dec (void *); // decrement a digit value
void inA (void *); // increment value of a character (' ' to '~')
void inc (void *); // increment a digit value
void up (void *); // increment value of parameter
void dn (void *); // decrement value of paramter
void dspA (void *); // display string for edit
void dspP (void *); // display parameter for edit
void dspV (void *); // display variable for edit
void menu (MenuStim_t);
#endif
Start by figuring out what attributes a menu item would need and what it will do when selected. Design a few fictitious menus to help with this and then as you build your code, use them to verify that all the items you imagined could be handled.
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