Dining Philosophers Problem
Author
Could someone give me a good solution for Dining Philosophers Problem in UNIX C, using semaphores and shared memory.
I figured, I remember doing this one back in school. Any particular reason you just aren''t doing this one yourself?
It only takes 50 or so lines as I recall.
It only takes 50 or so lines as I recall.
I went to WPI. They cover this in an operating systems course, same as you're taking.
[edited by - cheesegrater on May 28, 2003 2:47:55 PM]
[edited by - cheesegrater on May 28, 2003 2:47:55 PM]
Author
WPI is an institude,not a school. Anyway,do you know an efficient algorithm to my problem cos i have now power and time for it :-)
my C is a bit rusty, but here goes:
void dine(int n){ if(n==0) { printf("Fuck it, let''s order pizza\n"); } else { printf("I want pepperoni!\n"); }}int main(){ for(int i=0;i<5;i++) { if(fork()) { dine(i); return 0; } } return 0;}
Hey, we all called it a ''school'' while we were going there.
If you don''t have to worry about fairness, it''s sufficient to represent each utensil as a binary semaphore. You also add an additional semaphore you need to lock before picking up any utensils. That''ll make your philosophers eat one at a time and keep them from getting deadlocked.
If you don''t have to worry about fairness, it''s sufficient to represent each utensil as a binary semaphore. You also add an additional semaphore you need to lock before picking up any utensils. That''ll make your philosophers eat one at a time and keep them from getting deadlocked.
utensil[0...4]
while(true)
{
think();
test(#utensils);
test(utensil);
take(utensil);<br> test(utensil[i+1 % 5]);<br> take (utensil[i+1 % 5]);<br> eat();<br> put_back(utensil);<br> free(utensil);<br> put_back(utensil);<br> free(utensil);<br> free(#utensils);<br>} </i> <br><br><br><br><SPAN CLASS=editedby>[edited by - Raab314159 on May 28, 2003 3:14:11 PM]</SPAN>
while(true)
{
think();
test(#utensils);
test(utensil);
take(utensil);<br> test(utensil[i+1 % 5]);<br> take (utensil[i+1 % 5]);<br> eat();<br> put_back(utensil);<br> free(utensil);<br> put_back(utensil);<br> free(utensil);<br> free(#utensils);<br>} </i> <br><br><br><br><SPAN CLASS=editedby>[edited by - Raab314159 on May 28, 2003 3:14:11 PM]</SPAN>
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