#4 Producer and consumer problem. Modify the given boundedBuffer.c program to add the following two features: a. allow multiple producers and multiple consumers. b. change the buffer size from 1 to n. n should be a command line parameter. (In the main thread, create 3 producers and 3 consumers.)

// boundedBuffer.c

#include #include #include #include #define SHARED 1 void *Producer (void *); // the two threads void *Consumer (void *); sem_t empty, full; //global semaphores int data; // shared buffer, size = 1 int numIters; // main() -- read command line and create threads int main(int argc, char *argv[]) { pthread_t pid, cid; sem_init(&empty, SHARED, 1); // sem empty = 1 sem_init(&full, SHARED, 0); //sem full = 0 if (argc < 2) { printf("Usage: boundedBuffer "); exit(0); } numIters = atoi(argv[1]); pthread_create(&pid, NULL, Producer, NULL); pthread_create(&cid, NULL, Consumer, NULL); pthread_join(pid, NULL); pthread_join(cid, NULL); pthread_exit(0); } // deposit 1, ..., numIters into the data buffer void *Producer(void *arg) { int produced; for (produced = 0; produced < numIters; produced++) { sem_wait(&empty); data = produced; sem_post(&full); } } //fetch numIters items from the buffer and sum them void *Consumer(void *arg) { int total = 0; int consumed; for (consumed = 0; consumed < numIters; consumed++) { sem_wait(&full); total = total + data; sem_post(&empty); } printf("the total is %d ", total); }