Update Dining_Philosophore_Semaphore.CPP

Author: RChandana

Dining_Philosophore_Semaphore.CPP

@@ -1 +1,112 @@
+#include <stdio.h>
+#include <iostream>
+#include <pthread.h>
+#include <unistd.h>
+using namespace std;
 
+#define N 10
+#define THINKING 2
+#define HUNGRY 1
+#define EATING 0
+#define LEFT (phnum + 4) % N
+#define RIGHT (phnum + 1) % N
+
+int phil[N];
+int times = 200;
+
+class monitor {
+	int state[N];
+	pthread_cond_t phcond[N];
+	pthread_mutex_t condLock;
+
+public:
+	void test(int phnum){
+        if (state[(phnum + 1) % 5] != EATING
+			and state[(phnum + 4) % 5] != EATING
+			and state[phnum] == HUNGRY) {
+			state[phnum] = EATING;
+
+			pthread_cond_signal(&phcond[phnum]);
+		}
+	}
+
+	void take_fork(int phnum){
+        pthread_mutex_lock(&condLock);
+		state[phnum] = HUNGRY;
+		test(phnum);
+		if (state[phnum] != EATING) {
+			pthread_cond_wait(&phcond[phnum], &condLock);
+		}
+		cout << "Philosopher " << phnum << " is Eating"
+			<< endl;
+
+		pthread_mutex_unlock(&condLock);
+	}
+
+	void put_fork(int phnum){
+        pthread_mutex_lock(&condLock);
+		state[phnum] = THINKING;
+
+		test(RIGHT);
+		test(LEFT);
+
+		pthread_mutex_unlock(&condLock);
+	}
+
+	monitor(){
+		for (int i = 0; i < N; i++) {
+			state[i] = THINKING;
+		}
+
+		for (int i = 0; i < N; i++) {
+			pthread_cond_init(&phcond[i], NULL);
+		}
+
+		pthread_mutex_init(&condLock, NULL);
+	}
+
+	~monitor(){
+		for (int i = 0; i < N; i++) {
+			pthread_cond_destroy(&phcond[i]);
+		}
+
+		pthread_mutex_destroy(&condLock);
+	}
+}
+phil_object;
+void* philosopher(void* arg){
+	int c = 0;
+	while (c < times) {
+		int i = *(int*)arg;
+		sleep(1);
+		phil_object.take_fork(i);
+		sleep(0.5);
+		phil_object.put_fork(i);
+		c++;
+	}
+}
+
+int main(){
+	pthread_t thread_id[N];
+	pthread_attr_t attr;
+	pthread_attr_init(&attr);
+	pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
+
+	for (int i = 0; i < N; i++) {
+		phil[i] = i;
+	}
+
+	for (int i = 0; i < N; i++) {
+		pthread_create(&thread_id[i], &attr, philosopher, &phil[i]);
+		cout << "Philosopher " << i + 1 << " is thinking..." << endl;
+	}
+
+	for (int i = 0; i < N; i++) {
+		pthread_join(thread_id[i], NULL);
+	}
+
+	pthread_attr_destroy(&attr);
+	pthread_exit(NULL);
+
+	return 0;
+}