3

#include<stdio.h>
#include<semaphore.h>
#include<pthread.h>
//Number of Philosophers
#define M 5
//Think
#define THINK 0
//Hungry
#define HUNGRY 1
//Eat
#define EAT 2
//Left chopstick
#define LEFTCHOP (phNum+4)%M
//Right chopstick
#define RIGHTCHOP (phNum+1)%M
//Semaphore variables
sem_t ourMutex;
sem_t S[M];
//Declare the needed methods
void* diningPhilospher(void* number);
void takeFork(int);
void putFork(int);
void tester(int);
//Declare the needed array
int state[M];
int philNum[M] = { 0,1,2,3,4 };
//Driver
int main()
{
	//Declare the needed variable
	int j;

	//Declare a thread
	pthread_t threadID[M];

	//Initialize
	sem_init(&ourMutex, 0, 1);

	//Loop
	for (j = 0;j < M;j++)

		//Initialize
		sem_init(&S[j], 0, 0);

	//Loop
	for (j = 0;j < M;j++)
	{
		//Create thread
		pthread_create(&threadID[j], NULL, diningPhilospher, &philNum[j]);

		//Display message
		printf("Philosopher %d is thinking\n", j + 1);
	}

	//Loop
	for (j = 0;j < M;j++)

		//Thread
		pthread_join(threadID[j], NULL);
}
//Method definition diningPhilospher()
void* diningPhilospher(void* number)
{
	//Loop
	while (1)
	{
		//Initialize
		int* j = number;

		//Function call
		takeFork(*j);

		//Function call
		putFork(*j);
	}
}
//Method definition
void takeFork(int phNum)
{
	//Wait
	sem_wait(&ourMutex);

	//Update state
	state[phNum] = HUNGRY;

	//Display
	printf("Philosopher %d is Hungry\n", phNum + 1);

	//Function call
	tester(phNum);
	sem_post(&ourMutex);

	//Wait
	sem_wait(&S[phNum]);
}
//Method definition
void tester(int phNum)
{
	//Condition check
	if (state[phNum] == HUNGRY && state[LEFTCHOP] != EAT && state[RIGHTCHOP] != EAT)
	{
		//State
		state[phNum] = EAT;
		//Display
		printf("Philosopher %d takes fork %d and %d\n", phNum + 1, LEFTCHOP + 1, phNum + 1);

		//Display
		printf("Philosopher %d is Eating\n", phNum + 1);
		sem_post(&S[phNum]);
	}
}
//Method definition
void putFork(int phNum)
{
	//Wait
	sem_wait(&ourMutex);

	//State
	state[phNum] = THINK;

	//Display
	printf("Philosopher %d putting fork %d and %d down\n", phNum + 1, LEFTCHOP + 1, phNum + 1);

	//Display
	printf("Philosopher %d is thinking\n", phNum + 1);

	//Function call
	tester(LEFTCHOP);

	//Function call
	tester(RIGHTCHOP);
	sem_post(&ourMutex);
}