How to write c programme of Sleeping-barber problem in opertating system?

Answer 1

#define CHAIRS 5 /* # chairs for waiting customers */

typedef int semaphore; /* use your imagination */

semaphore customers = 0; /* # of customers waiting for service */

semaphore barbers = 0; /* # of barbers waiting for customers */

semaphore mutex = 1; /* for mutual exclusion */

int waiting = 0; /* customer are waiting (not being cut) */

void barber(void)

{

while (TRUE) {

down(&customers); /* go to sleep if # of customers is 0 */

down(&mutex); /* acquire access to "waiting' */

waiting = waiting - 1; /* decrement count of waiting customers */

up(&barbers); /* one barber is now ready to cut hair */

up(&mutex); /* release 'waiting' */

cut_hair(); /* cut hair (outside critical region */

}

}

void customer(void)

{

down(&mutex); /* enter critical region */

if (waiting < CHAIRS) { /* if there are no free chairs, leave */

waiting = waiting + 1; /* increment count of waiting customers */

up(&customers); /* wake up barber if necessary */

up(&mutex); /* release access to 'waiting' */

down(&barbers); /* go to sleep if # of free barbers is 0 */

get_haircut(); /* be seated and be served */

} else {

up(&mutex); /* shop is full; do not wait */

}

}