Use Posix Thread to do the following activity. Write a program that creates two

Question

Use Posix Thread to do the following activity. Write a program that creates two threads, one reading a text you create that contains a series of none-zero numbers ended by a special number -1 and stores the numbers , including the ending -1, into an array, while the other thread write the numbers in the array to a newly created text file in the same directory. Note: make sure the thread that writes the numbers to file come back to read the array until -1 is encountered, if the writing is faster than the reading. You need to figure out how to tell the writing thread where is the last item that has been read into the array when the reading is still ongoing.

Explanation / Answer

#include<stdio.h>
#include<pthread.h>
#include<semaphore.h>

sem_t readCountAccess;
sem_t databaseAccess;
int readCount=0;

void *Reader(void *arg);
void *Writer(void *arg);

int main()
{
int i=0,NumberofReaderThread=0,NumberofWriterThread;
sem_init(&readCountAccess,0,1);
sem_init(&databaseAccess,0,1);

pthread_t Readers_thr[100],Writer_thr[100];
printf(“ Enter number of Readers thread(MAX 10)”);
scanf(“%d”,&NumberofReaderThread);
printf(“ Enter number of Writers thread(MAX 10)”);
scanf(“%d”,&NumberofWriterThread);

for(i=0;i<numberofreaderthread;i++)
{
pthread_create(&Readers_thr[i],NULL,Reader,(void *)i);
}
for(i=0;i<numberofwriterthread;i++)
{
pthread_create(&Writer_thr[i],NULL,Writer,(void *)i);
}
for(i=0;i<NumberofWriterThread;i++)
{
pthread_join(Writer_thr[i],NULL);
}

for(i=0;i<NumberofReaderThread;i++)
{
pthread_join(Readers_thr[i],NULL);
}
sem_destroy(&databaseAccess);
sem_destroy(&readCountAccess);
return 0;
}

void * Writer(void *arg)
{
sleep(1);
int temp=(int)arg;
printf(“ Writer %d is trying to enter into database for modifying the data”,temp);
sem_wait(&databaseAccess);
printf(“ Writer %d is writting into the database”,temp);
printf(“ Writer %d is leaving the database”);
sem_post(&databaseAccess);
}

void *Reader(void *arg)
{
sleep(1);
int temp=(int)arg;
printf(“ Reader %d is trying to enter into the Database for reading the data”,temp);
sem_wait(&readCountAccess);
readCount++;
if(readCount==1)
{
sem_wait(&databaseAccess);
printf(“ Reader %d is reading the database”,temp);
}
sem_post(&readCountAccess);
sem_wait(&readCountAccess);
readCount–;
if(readCount==0)
{
printf(“ Reader %d is leaving the database”,temp);
sem_post(&databaseAccess);
}
sem_post(&readCountAccess);
}

Outputs Is :

Enter number of Readers thread(MAX 10)2

Enter number of Writers thread(MAX 10)1

Reader 0 is trying to enter into the Database for reading the data
Reader 0 is reading the database
Reader 0 is leaving the database
Reader 1 is trying to enter into the Database for reading the data
Reader 1 is reading the database
Reader 1 is leaving the database
Writer 0 is trying to enter into database for modifying the data
Writer 0 is writing into the database
Writer 0 is leaving the database

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