pi

#!../c99sh -m

long long niter = argc > 1 ? atof(argv[1]) : 100000;
long long count = 0;

#pragma omp parallel
{
    unsigned int seed = omp_get_thread_num();

    #pragma omp for reduction(+: count) schedule(static)
    for (long long i = 0; i < niter; ++i) {
        const double x = rand_r(&seed) / (double) RAND_MAX;
        const double y = rand_r(&seed) / (double) RAND_MAX;
        count += sqrt(x*x + y*y) < 1;
    }

}

printf("%lld: %g\n", niter, M_PI - 4*(count / (double) niter));

// vim:syntax=c