i need the code in C please ,,,, POSIX Synchronization In the Sleeping-Barber pr

Question

i need the code in C please ,,,,
POSIX Synchronization
In the Sleeping-Barber problem, a barbershop consists of a waiting room with n chairs and one barber chair. If there are no customers to be served, the barber goes to sleep. If a customer enters the barbershop and the barber is asleep, the customer wakes up the barber. If the barber is busy but chairs are available, then the customer sits in FCFS free chairs. If all chairs are occupied, then the customer is blocked. Using POSIX semaphores, write a program to synchronize the operations of the barber and the customers. Your program should display all barbershop operations. Note: waiting room size n should be initialized by user on the command line.
i need the code in C please ,,,,
POSIX Synchronization
In the Sleeping-Barber problem, a barbershop consists of a waiting room with n chairs and one barber chair. If there are no customers to be served, the barber goes to sleep. If a customer enters the barbershop and the barber is asleep, the customer wakes up the barber. If the barber is busy but chairs are available, then the customer sits in FCFS free chairs. If all chairs are occupied, then the customer is blocked. Using POSIX semaphores, write a program to synchronize the operations of the barber and the customers. Your program should display all barbershop operations. Note: waiting room size n should be initialized by user on the command line.
i need the code in C please ,,,,
POSIX Synchronization
In the Sleeping-Barber problem, a barbershop consists of a waiting room with n chairs and one barber chair. If there are no customers to be served, the barber goes to sleep. If a customer enters the barbershop and the barber is asleep, the customer wakes up the barber. If the barber is busy but chairs are available, then the customer sits in FCFS free chairs. If all chairs are occupied, then the customer is blocked. Using POSIX semaphores, write a program to synchronize the operations of the barber and the customers. Your program should display all barbershop operations. Note: waiting room size n should be initialized by user on the command line.

Explanation / Answer

#
define _REENTRANT

# include < stdio.h >

#include < unistd.h >

#include < stdlib.h >

#include < pthread.h >

#include < semaphore.h >

// The maximum number of customer threads.

#define MAX_CUSTOMERS 25

// Function prototypes...

void * customer(void * num);

void * barber(void * );

void randwait(int secs);

// Define the semaphores.

// waitingRoom Limits the # of customers allowed

// to enter the waiting room at one time.

sem_t waitingRoom;

// barberChair ensures mutually exclusive access to

// the barber chair.

sem_t barberChair;

// barberPillow is used to allow the barber to sleep

// until a customer arrives.

sem_t barberPillow;

// seatBelt is used to make the customer to wait until

// the barber is done cutting his/her hair. sem_t seatBelt;

// Flag to stop the barber thread when all customers

// have been serviced.

int allDone = 0;

int main(int argc, char * argv[]) {
pthread_t btid;

pthread_t tid[MAX_CUSTOMERS];

long RandSeed;

int i, numCustomers, numChairs;

int Number[MAX_CUSTOMERS];

// Check to make sure there are the right number of

// command line arguments.

if (argc != 4) {

printf("Use: SleepBarber <Num Customers> <Num Chairs> <rand seed> ");

exit(-1);

}

// Get the command line arguments and convert them

// into integers.

numCustomers = atoi(argv[1]);

numChairs = atoi(argv[2]);

RandSeed = atol(argv[3]);

// Make sure the number of threads is less than the number of

// customers we can support.

if (numCustomers > MAX_CUSTOMERS) {

printf("The maximum number of Customers is %d. ", MAX_CUSTOMERS);

exit(-1);

}

printf(" SleepBarber.c ");

printf("A solution to the sleeping barber problem using semaphores. ");

// Initialize the random number generator with a new seed.

srand48(RandSeed);

// Initialize the numbers array.

for (i = 0; i < MAX_CUSTOMERS; i++) {

Number[i] = i;

}

// Initialize the semaphores with initial values...

sem_init( & waitingRoom, 0, numChairs);

sem_init( & barberChair, 0, 1);

sem_init( & barberPillow, 0, 0);

sem_init( & seatBelt, 0, 0);

// Create the barber. pthread_create(&btid, NULL, barber, NULL);

// Create the customers.

for (i = 0; i < numCustomers; i++) {

pthread_create( & tid[i], NULL, customer, (void * ) & Number[i]);

}

// Join each of the threads to wait for them to finish.

for (i = 0; i < numCustomers; i++) {

pthread_join(tid[i], NULL);

}

// When all of the customers are finished, kill the

// barber thread.

allDone = 1;

sem_post( & barberPillow);

// Wake the barber so he will exit.

pthread_join(btid, NULL);

}

void * customer(void * number) {

int num = * (int * ) number;

// Leave for the shop and take some random amount of

// time to arrive.

printf("Customer %d leaving for barber shop. ", num);

randwait(5);

printf("Customer %d arrived at barber shop. ", num);

// Wait for space to open up in the waiting room...

sem_wait( & waitingRoom);

printf("Customer %d entering waiting room. ", num);

// Wait for the barber chair to become free.

sem_wait( & barberChair);

// The chair is free so give up your spot in the

// waiting room.

sem_post( & waitingRoom);

// Wake up the barber...

printf("Customer %d waking the barber. ", num);

sem_post( & barberPillow);

// Wait for the barber to finish cutting your hair.

sem_wait( & seatBelt);

// Give up the chair.

sem_post( & barberChair);

printf("Customer %d leaving barber shop. ", num);

}

void * barber(void * junk) {

// While there are still customers to be serviced...

// Our barber is omnicient and can tell if there are

// customers still on the way to his shop.

while (!allDone) {

// Sleep until someone arrives and wakes you..

printf("The barber is sleeping ");

sem_wait( & barberPillow);

// Skip this stuff at the end...

if (!allDone) {

// Take a random amount of time to cut the

// customer's hair.

printf("The barber is cutting hair ");

randwait(3);

printf("The barber has finished cutting hair. ");

// Release the customer when done cutting...

sem_post( & seatBelt);

} else {

printf("The barber is going home for the day. ");

}

}

}

void randwait(int secs) {

int len;

// Generate a random number...

len = (int)((drand48() * secs) + 1);

sleep(len);

}

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