Dining Philosopher Program in C - Operating Systems

 # include<stdio.h>
# include<pthread.h>
# include<semaphore.h>

sem_t fork[100];
int n;

void *phil_job(int no)
{
printf("\nPhilosopher %d is thinking",no+1);

sem_wait(&fork[no]);
sem_wait(&fork[(no+1)%n]);

printf("\nPhilosopher %d started eating",no+1);
sleep(1);
printf("\nPhilosopher %d finished eating",no+1);
sem_post(&fork[(no+1)%n]);
sem_post(&fork[no]);
}


void main()
{

int i;
pthread_t phil_thread[100];

printf("\nEnter the number of philosopher :");
scanf("%d",&n);

for(i=0;i<n;++i)
if(sem_init(&fork[i],0,1)==-1)
{
perror("semaphore initialization failed");
exit(1);
}

for(i=0;i<n;++i)
{
if(pthread_create(&phil_thread[i],NULL,phil_job,(int*) i)!=0)
{
perror("semaphore creation failed");
exit(1);
}

}



for(i=0;i<n;++i)
if(pthread_join(phil_thread[i],NULL)!=0)
{
perror("semaphore join failed");
exit(1);
}



printf("\n \n thread join succesfull\n");

for(i=0;i<n;++i)
if(sem_destroy(&fork[i])==-1)
{
perror("semaphore destruction failed");
exit(1);

}
}

OUTPUT:

Enter the number of philosopher :5

Philosopher 1 is thinking
Philosopher 2 is thinking
Philosopher 1 started eating
Philosopher 4 is thinking
Philosopher 4 started eating
Philosopher 3 is thinking
Philosopher 5 is thinking
Philosopher 4 finished eating
Philosopher 1 finished eating
Philosopher 3 started eating
Philosopher 5 started eating
Philosopher 3 finished eating
Philosopher 2 started eating
Philosopher 5 finished eating
Philosopher 2 finished eating

 thread join succesfull