#include <stdio.h>
 
 
struct flagtype
{
    unsigned char a: 2;
    unsigned int b: 1;
    unsigned char c : 1;
    unsigned char d : 4;
};
 
union utype {
    struct flagtype f;
    unsigned char byte;
};
 
 
int main(int argc, char* argv[])
{
    union utype u;
    int x;
    u.byte=0;
    printf("Size of u = %d\n",sizeof(u));
    u.f.a=3;
    u.f.b=0;
    u.f.c=0;
    u.f.d=15;
    printf("Byte = %d",u.byte);
    x=u.f.d;
    return 0;
}

    printf("sizeof(struct flagtype) = %d\n", sizeof(struct flagtype));
    printf("Size of u               = %d\n", sizeof(u));

// Well i think atleast you will have an idea how to use the bit operations 
// to achieve the desired results.
// Using 'OR' operation you can turn on any bit without effecting the status
// of other bits.
// Similarly if you use 'AND' operation on byte then you can turn off any
// desired bit without effecting the rest.
// i may not chek this forum any more but if you have any queries ....
// [email]shibinkidd@gmail.com[/email]

// NB: this is for demo only.... i strictly suggest u not to use the global variables.


#define ON  1
#define OFF 0
char cBulb1,cBulb2,cBulb3,cShutter1,cShutter2,cShuter3,cMotor1,cMotor2;
char cStatus;
void updateStatus(){

  if(cBulb1 == ON) cStatus |= 0x80;
  else cStatus  &= 0x7F;

  if(cBulb2 == ON) cStatus |= 0x40;
  else cStatus  &= 0xBF;
  
  if(cBulb3 == ON) cStatus |= 0x20;
  else cStatus  &= 0xDF;

  if(cShutter1 == ON) cStatus |= 0x10;
  else cStatus  &= 0xEF;
 
  if(cShutter2 == ON) cStatus |= 0x08;
  else cStatus  &= 0xF7;
  
  if(cShutter3 == ON) cStatus |= 0x04;
  else cStatus  &= 0xFB;

  if(cMotor1 == ON) cStatus |= 0x02;
  else cStatus  &= 0xFD;

  if(cMotor1 == ON) cStatus |= 0x01;
  else cStatus  &= 0xFE;

}

main(){


    cBulb1 =  ON;
    cBulb2 =  OFF;
    cBulb3 =  OFF;
    cShutter1 = ON;
    cShutter2 = ON;
    cShuter3  = OFF;
    cMotor1   =  ON;
    cMotor2   = ON;
    
//      cStatus bit allocation is as given below.
//MSB   7       6        5         4              3            2         1          0       LSB
//    cBulb1 cBulb2 cBulb3 cShutter1 cShutter2 cShuter3 cMotor1 cMotor2
//

   updateStatus();

   while(1){}

}