1#include 2 #include #include 4 #include 3 5 sem_t fork[3]; 6 7 void eat (int phil) { 8 printf("Philosopher %d is eating\n", phil); sleep (2); //time eating 9 10) 11 void philosopher (void * num) { int phil-(int *)num; 12 13 14 printf("Philosopher %d wants to eat\n",phil); sem_wait(&fork[phil]); 15 sem_wait (&fork[(phil+1)]); 16 eat (phil); 17 18 printf("Philosopher %d has finished eating\n",phil); sem_post(&fork[(phil+1)]); sem_post(&fork[phil]); 19 20) 21 int main(){ 22 int i,a[3]; 23 pthread_t tid[3]; for(i=0;i<3;i++) 24 25 sem_init(&fork [1],0,1); 26 for(i=0;i<3;i++){ 27 a[i]-i; 28 pthread_create(&tid[i], NULL, philosopher, (void *)&a[i]); 29 30 for(i=0;i<3;i++) 31 pthread_join(tid[i],NULL); 32) Fig.1 Figure 1 shows a program that tries to solve the dining philosophers' problem given that it only includes 3 philosophers who want to eat, where only 3 forks are available and each philosopher needs two forks. The outputs after running the program are given in Figure 2. In the outputs, it seems that the program never finishes executing; thus, (a) explain the reasons why it never finishes (b) which lines of the code in Figure 1 are considered critical section? (c) which lines of the code is (or should be) implemented as atomic operations. Philosopher 2 wants to eat Philosopher 1 wants to eat Philosopher wants to eat Fig.2 Outputs generated from the code above
1#include 2 #include #include 4 #include 3 5 sem_t fork[3]; 6 7 void eat (int phil) { 8 printf("Philosopher %d is eating\n", phil); sleep (2); //time eating 9 10) 11 void philosopher (void * num) { int phil-(int *)num; 12 13 14 printf("Philosopher %d wants to eat\n",phil); sem_wait(&fork[phil]); 15 sem_wait (&fork[(phil+1)]); 16 eat (phil); 17 18 printf("Philosopher %d has finished eating\n",phil); sem_post(&fork[(phil+1)]); sem_post(&fork[phil]); 19 20) 21 int main(){ 22 int i,a[3]; 23 pthread_t tid[3]; for(i=0;i<3;i++) 24 25 sem_init(&fork [1],0,1); 26 for(i=0;i<3;i++){ 27 a[i]-i; 28 pthread_create(&tid[i], NULL, philosopher, (void *)&a[i]); 29 30 for(i=0;i<3;i++) 31 pthread_join(tid[i],NULL); 32) Fig.1 Figure 1 shows a program that tries to solve the dining philosophers' problem given that it only includes 3 philosophers who want to eat, where only 3 forks are available and each philosopher needs two forks. The outputs after running the program are given in Figure 2. In the outputs, it seems that the program never finishes executing; thus, (a) explain the reasons why it never finishes (b) which lines of the code in Figure 1 are considered critical section? (c) which lines of the code is (or should be) implemented as atomic operations. Philosopher 2 wants to eat Philosopher 1 wants to eat Philosopher wants to eat Fig.2 Outputs generated from the code above
Computer Networking: A Top-Down Approach (7th Edition)
7th Edition
ISBN:9780133594140
Author:James Kurose, Keith Ross
Publisher:James Kurose, Keith Ross
Chapter1: Computer Networks And The Internet
Section: Chapter Questions
Problem R1RQ: What is the difference between a host and an end system? List several different types of end...
Related questions
Question
![1#include<stdio.h>
2 #include<pthread.h>
#include<semaphore.h>
4 #include<unistd.h>
3
5 sem_t fork[3];
6
7 void eat (int phil) {
8
printf("Philosopher %d is eating\n", phil);
sleep (2); //time eating
9
10}
11 void
philosopher (void * num) {
int phil-*(int *)num;
12
13
printf("Philosopher %d wants to eat\n", phil);
14
sem_wait (&fork[phil]);
15
sem_wait (&fork [(phil+1)]);
16
eat (phil);
17
18
printf("Philosopher %d has finished eating\n",phil);
sem_post(&fork [(phil+1)]);
sem_post(&fork[phil]);
19
20}
21 int main(){
22
int i, a[3];
23
pthread_t tid[3];
for(i=0;i<3; i++)
24
25
sem_init(&fork[i],0,1);
26
for(i=0;i<3; i++){
27
a[i]=i;
28
pthread_create(&tid[i], NULL, philosopher, (void *)&a[i]);
29
}
30
for(i=0;i<3;i++)
31
pthread_join(tid[i],NULL);
32}
Fig.1
Figure 1 shows a program that tries to solve the dining philosophers' problem given that it only
includes 3 philosophers who want to eat, where only 3 forks are available and each philosopher
needs two forks. The outputs after running the program are given in Figure 2. In the outputs, it
seems that the program never finishes executing; thus,
(a) explain the reasons why it never finishes
(b) which lines of the code in Figure 1 are considered critical section?
(c) which lines of the code is (or should be) implemented as atomic operations.
Philosopher 2 wants to eat
Philosopher 1 wants to eat
Philosopher 0 wants to eat
Fig.2 Outputs generated from the code above](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fe81df371-77c6-40d5-bf28-c6c10cde1ca7%2F8cc21184-164f-4433-a2dd-d254802886d7%2F3lhkdu_processed.png&w=3840&q=75)
Transcribed Image Text:1#include<stdio.h>
2 #include<pthread.h>
#include<semaphore.h>
4 #include<unistd.h>
3
5 sem_t fork[3];
6
7 void eat (int phil) {
8
printf("Philosopher %d is eating\n", phil);
sleep (2); //time eating
9
10}
11 void
philosopher (void * num) {
int phil-*(int *)num;
12
13
printf("Philosopher %d wants to eat\n", phil);
14
sem_wait (&fork[phil]);
15
sem_wait (&fork [(phil+1)]);
16
eat (phil);
17
18
printf("Philosopher %d has finished eating\n",phil);
sem_post(&fork [(phil+1)]);
sem_post(&fork[phil]);
19
20}
21 int main(){
22
int i, a[3];
23
pthread_t tid[3];
for(i=0;i<3; i++)
24
25
sem_init(&fork[i],0,1);
26
for(i=0;i<3; i++){
27
a[i]=i;
28
pthread_create(&tid[i], NULL, philosopher, (void *)&a[i]);
29
}
30
for(i=0;i<3;i++)
31
pthread_join(tid[i],NULL);
32}
Fig.1
Figure 1 shows a program that tries to solve the dining philosophers' problem given that it only
includes 3 philosophers who want to eat, where only 3 forks are available and each philosopher
needs two forks. The outputs after running the program are given in Figure 2. In the outputs, it
seems that the program never finishes executing; thus,
(a) explain the reasons why it never finishes
(b) which lines of the code in Figure 1 are considered critical section?
(c) which lines of the code is (or should be) implemented as atomic operations.
Philosopher 2 wants to eat
Philosopher 1 wants to eat
Philosopher 0 wants to eat
Fig.2 Outputs generated from the code above
Expert Solution
This question has been solved!
Explore an expertly crafted, step-by-step solution for a thorough understanding of key concepts.
Step by step
Solved in 3 steps
Recommended textbooks for you
Computer Networking: A Top-Down Approach (7th Edi…
Computer Engineering
ISBN:
9780133594140
Author:
James Kurose, Keith Ross
Publisher:
PEARSON
Computer Organization and Design MIPS Edition, Fi…
Computer Engineering
ISBN:
9780124077263
Author:
David A. Patterson, John L. Hennessy
Publisher:
Elsevier Science
Network+ Guide to Networks (MindTap Course List)
Computer Engineering
ISBN:
9781337569330
Author:
Jill West, Tamara Dean, Jean Andrews
Publisher:
Cengage Learning
Computer Networking: A Top-Down Approach (7th Edi…
Computer Engineering
ISBN:
9780133594140
Author:
James Kurose, Keith Ross
Publisher:
PEARSON
Computer Organization and Design MIPS Edition, Fi…
Computer Engineering
ISBN:
9780124077263
Author:
David A. Patterson, John L. Hennessy
Publisher:
Elsevier Science
Network+ Guide to Networks (MindTap Course List)
Computer Engineering
ISBN:
9781337569330
Author:
Jill West, Tamara Dean, Jean Andrews
Publisher:
Cengage Learning
Concepts of Database Management
Computer Engineering
ISBN:
9781337093422
Author:
Joy L. Starks, Philip J. Pratt, Mary Z. Last
Publisher:
Cengage Learning
Prelude to Programming
Computer Engineering
ISBN:
9780133750423
Author:
VENIT, Stewart
Publisher:
Pearson Education
Sc Business Data Communications and Networking, T…
Computer Engineering
ISBN:
9781119368830
Author:
FITZGERALD
Publisher:
WILEY