Answer:
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
pthread_mutex_t mutex;
int fib[10]; /* this data is shared by the thread(s) */
int in = 0;
void *genFibo(void *param); /* the thread */
int main(int argc, char *argv[])
{
pthread_attr_t attr;
if (argc != 2) {
fprintf(stderr,"usage: fibthread <integer value>\n");
return -1;
}
int count = atoi(argv[1]);
if (count < 1) {
fprintf(stderr,"%d must be>= 1\n", count);
return -1;
}
pthread_attr_init(&attr);
// Mutex Lock
pthread_mutex_init(&mutex, NULL);
// each thread computes fibonacci
for(int i = 1;i <= count;i++) {
pthread_t thread;
pthread_create(&thread, &attr, genFibo, (void*)i);
pthread_join(thread, NULL);
}
// print resulting array
for (int i = 0; i < in;i++) {
printf("%d ", fib[i]);
}
printf("\n");
pthread_mutex_destroy(&mutex);
}
void *genFibo(void *param)
{
pthread_mutex_lock(&mutex);
fib[in++] = fibonacci((int)param);
pthread_mutex_unlock(&mutex);
pthread_exit(0);
}
int fibonacci (int x)
{
if (x <= 1) {
return 1;
}
return fibonacci(x-1) + fibonacci(x-2);
}
