#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <lib.h>

#include <sys/cdefs.h>

#include <sys/wait.h>

#include <sys/types.h>

#include <sys/ipc.h>

#include <sys/shm.h>

#include <unistd.h>

#include <libsem.h>

#define MIN_THINK 1

#define MAX_THINK 7

#define MIN_EAT 1

#define MAX_EAT 7

#define N 5 /* number of philosophers */

#define LEFT (i+N-1)%N /* number of i's left neighbor */

#define RIGHT (i+1)%N /* number of i's right neighbor */

#define THINKING 0 /* philosopher is thinking */

#define HUNGRY 1 /* philosopher is trying to get forks */

#define EATING 2 /* philosopher is eating */

int *status; /* a pointer to keep track of the states of the philosophers */

int shmid;

key_t key;

int time;

char t;

int l;

// prototypes of the functions

void philosopher (int);

void put_forks(int);

void test (int);

void take_forks(int);

// end of the function prototypes

int diningphilosopher()

{

status= shmat(shmid, (void *)0, 0);

for(int i=0;i<N;i++)

{

createsem(i);

}

for(int i=0;i<N; i++)

{

// All the philosophers are thinking initially

status[i]=THINKING;

}

for(int i=0;i<N;i++)

{

int a =fork();

if(a!=0)

{

// I am in the parent

}

else

{

down(i);

philosopher(i);

printf("status of philosopher %d = %d\n", i+1, status[i]);

}

}

return 0;

} // end of dining philosopher function

void take_forks(int i) /* i: philosopher number, from 0 to N1 */

{

down(N); /* enter critical region */

status[i] = HUNGRY; /* record fact that philosopher i is hungry */

printf("philosopher %d is hungry\n", i+1);

test(i); /* try to acquire 2 forks */

sleep(3);

up(N); /* exit critical region */

down(i); /* block if forks were not acquired */

}

void put_forks(int i) /* i: philosopher number, from 0 to N1 */

{

down(N); /* enter critical region */

status[i] = THINKING; /* philosopher has finished eating */

test(LEFT); /* see if left neighbor can now eat */

sleep(3);

test(RIGHT); /* see if right neighbor can now eat */

sleep(3);

up(N); /* exit critical region */

}

void test(int i) /* i: philosopher number, from 0 to N1 */

{

if (status[i] == HUNGRY && status[LEFT] != EATING && status[RIGHT] != EATING)

{

status[i] = EATING;

up(i);

}

}

void philosopher(int i) /* i: philosopher number, from 0 to N1 */

{

printf("Philosopher %d is thinking\n", i+1);

time=rand() % MAX_THINK + MIN_THINK; /* philosopher is thinking */

sleep(time);

take_forks(i); /* acquire two forks or block */

printf("Philosopher %d is eating\n", i+1);

time=rand() % MAX_EAT + MIN_EAT;

sleep(time);

printf("Philosopher %d is done eating and back to thinking\n", i+1);

put_forks(i);

}

int main(void)

{

int in;

printf("Enter the number of tables you want \n");

scanf("%d", &in);

int k[in];

key_t key;

// generating a random key for shared memory

key=(int)(rand()%100+1);

// creating a shared memory of 1000 bytes

shmid = shmget(key, 1000 , 0644 | IPC_CREAT);

for(int i=0; i<in;i++)

{

int a=fork();

if(a!=0)

{

// I am in the parent

}

else

{

printf("Hey you are welcomed to the Dining Philosopher Demo \n");

printf("The number of the table is %d \n", i+1);

// function is called

diningphilosopher();

}

}

return 0;

// end of main function

}