Question

The goal of this assignment is to write a multithreaded program (Task3.c) that explores synchronization challenge 1. Assume that we have a shared variable CurrentiD. This is initialized to 1 at the beginning. 2. Now create 5 threads in your program and assign ID 1,2,3,4,5 to them respectively. You can pass the ID as a parameter when you create the threads. Each of the threads will try to access the variable "CurrentiD" Whenever a thread acquires the variable, it checks whether the Currentld is equal to its own ID or not. If it is not equal, it will output "Not My Turn!", then print its threadld, and then release the variable. Ifit is equal, the thread will print "My turn!", then print its threadld, increase the Currentld by 1 and then release the variable. However, after increasing CurrentID by 1, the thread will check if the value is 6 or not. If it is 6, it will reset it to 1 before releasing the variable 3. 4. 5. The program should execute until each thread prints "My Turn!" 10 times. Once a thread prints for 10 times, i terminates. Count the number of times each thread prints "Not my Turn!" and include that in the report.

Answer 1

CODE:

#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
int NextID = 1, total1 = 0, total2 = 0, total3=0, total4 = 0, total5 =0;

void *myThreadFun(void *vargp)
{
int myid = (int)vargp;
if(NextID == myid)
{
   printf("My Turn %d\n", myid);
   switch(NextID)
   {
       case 1: total1++; break;
       case 2: total2++; break;
       case 3: total3++; break;
       case 4: total4++; break;
       case 5: total5++; break;
   }
   NextID++;
   if(NextID == 6)
       NextID = 1;
}
else
{
   printf("Not My Turn %d\n", myid);
}
return NULL;
}
  
int main()
{
  
pthread_t tid1;
pthread_t tid2;
pthread_t tid3;
pthread_t tid4;
pthread_t tid5;
printf("Starting...\n");
while(total1 <20 || total2 < 20 || total3<20 || total4<20 || total5<20)
{
   pthread_create(&tid1, NULL, myThreadFun, (void*)1);
   pthread_create(&tid2, NULL, myThreadFun, (void*)2);
       pthread_create(&tid3, NULL, myThreadFun, (void*)3);
       pthread_create(&tid4, NULL, myThreadFun, (void*)4);
       pthread_create(&tid5, NULL, myThreadFun, (void*)5);
}
printf("Finishing..\n");
exit(0);
}
OUTPUT:

Starting...

Not My Turn 2

Not My Turn 3

Not My Turn 4

Not My Turn 5

My Turn 1

My Turn 2

My Turn 3

My Turn 4

My Turn 5

My Turn 1

Not My Turn 5

Not My Turn 4

Not My Turn 3

Not My Turn 1

My Turn 2

Not My Turn 2

My Turn 3

My Turn 4

My Turn 5

My Turn 1

My Turn 5

My Turn 1

Not My Turn 5

Not My Turn 1

My Turn 2

My Turn 3

My Turn 4

My Turn 5

My Turn 1

My Turn 2

My Turn 3

My Turn 4

Not My Turn 2

Not My Turn 3

Not My Turn 4

My Turn 5

My Turn 1

Not My Turn 4

Not My Turn 5

Not My Turn 1

My Turn 2

My Turn 3

My Turn 4

My Turn 5

My Turn 1

My Turn 2

My Turn 3

Not My Turn 3

My Turn 4

My Turn 5

My Turn 1

My Turn 2

Not My Turn 2

My Turn 3

My Turn 4

My Turn 5

My Turn 1

My Turn 2

My Turn 3

My Turn 4

My Turn 5

My Turn 1

Not My Turn 1

My Turn 2

My Turn 3

My Turn 4

My Turn 5

Not My Turn 5

My Turn 1

My Turn 2

My Turn 3

My Turn 4

My Turn 5

My Turn 1

My Turn 2

My Turn 3

My Turn 4

My Turn 5

My Turn 1

My Turn 2

My Turn 3

My Turn 4

My Turn 5

My Turn 1

My Turn 2

My Turn 3

My Turn 4

My Turn 5

My Turn 1

My Turn 2

My Turn 3

Not My Turn 2

Not My Turn 5

Not My Turn 1

Not My Turn 2

Not My Turn 3

My Turn 4

Not My Turn 2

Not My Turn 3

Not My Turn 4

My Turn 5

My Turn 1

My Turn 2

My Turn 3

My Turn 4

My Turn 5

Not My Turn 2

Not My Turn 3

Not My Turn 4

Not My Turn 5

My Turn 1

My Turn 2

Not My Turn 5

Not My Turn 1

Not My Turn 2

My Turn 3

My Turn 4

My Turn 5

My Turn 1

My Turn 2

My Turn 3

Number of times Thread1 missed the turn: 13

Number of times Thread2 missed the turn: 13

Number of times Thread3 missed the turn: 5

Number of times Thread4 missed the turn: 6

Number of times Thread5 missed the turn: 6

Finishing.........