Write a multithreaded program that generates the Fibonacci series using Pthreads thread library
Answers
Answer:
/*============================================================================
Description :The Fibonacci sequence
============================================================================ */
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
int n; // size of fibonacci sequence.
int *fibseq; // arry holds the value of each fibonacci term.
int i; // counter for the threads.
void *runn(void *arg);
int main(int argc, char *argv[])
{
if (argc != 2)
{
printf("format is:./a.out <intgervalue>\n");
return -1;
} // valdiate num of args.
if (atoi(argv[1]) < 0)
{
printf("%d must be>=0\n", atoi(argv[1]));
return -1;
} // valdiate value of arg1.
n = atoi(argv[1]);
fibseq = (int *)malloc(n * sizeof(int));
pthread_t *threads = (pthread_t *) malloc(n * sizeof(pthread_t));
pthread_attr_t attr; // set of thread attribute
pthread_attr_init(&attr);
for (i = 0; i < n; i++)
{
pthread_create(&threads[i], &attr, runn, NULL);
} // End of creating threads.
int j;
for (j = 0; j < n; j++)
{
pthread_join(threads[j], NULL);
} // End of wating the threads to exit.
// printing fibseq.
printf("The Fibonacci sequence.:");
int k;
for (k = 0; k < n; k++)
{
printf("%d,", fibseq[k]);
} // End of printing fibseq.
return 0;
} // End of main.
void *runn(void *arg)
{
if (i == 0)
{
fibseq[i] = 0;
pthread_exit(0);
} // first fib term
if (i == 1)
{
fibseq[i] = 1;
pthread_exit(0);
} // seconed fib term
else
{
fibseq[0] = 0;
fibseq[1] = 1;
fibseq[i] = fibseq[i - 1] + fibseq[i - 2];
// printf("fibseq[%d]%d,\n",i,fibseq[i]);
pthread_exit(0); // thread exit.
} // End of else
} // End of run.