bit_flags.c

#include <stdio.h>

const short FLAG_1 = 1;
const short FLAG_2 = 1 << 1;
const short FLAG_3 = 1 << 2;
const short FLAG_4 = 1 << 3;
   
//int settings = FLAG_1|FLAG_3|FLAG_4;
int settings = 0;

void set_flag(int flag);
void unset_flag(int flag);
int  is_flag_set(int flag);
int  is_flag_set_bool(int flag);

int main()
{
   
   
   printf("%d %d %d %d\n", FLAG_1, FLAG_2, FLAG_3, FLAG_4);
   
   printf("FLAG_2 set = %d\n", is_flag_set(FLAG_2));
   
   set_flag(FLAG_2);
   
   set_flag(FLAG_3);
   
   printf("FLAG_2 set = %d\n", is_flag_set(FLAG_2));
   printf("FLAG_3 set = %d\n", is_flag_set(FLAG_3));
   printf("FLAG_4 set = %d [0 = no, 1 = yes]\n", is_flag_set_bool(FLAG_4));
   
   unset_flag(FLAG_2);
   
   printf("FLAG_2 set = %d [0 = no, 1 = yes]\n", is_flag_set_bool(FLAG_2));
   
   set_flag(FLAG_4);
   
   printf("FLAG_4 set = %d [0 = no, 1 = yes]\n", is_flag_set_bool(FLAG_4));
   
   return 0;
}


void set_flag(int flag) {
     settings |= flag;
}

void unset_flag(int flag) {
    settings &= ~flag;    
}

int is_flag_set(int flag) {
    return settings & flag;
}
 
int is_flag_set_bool(int flag) {
    return (settings & flag) > 0 ? 1 : 0;
}