Update

Test/Test.c

@@ -0,0 +1,71 @@
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+#define NUM_THREADS 4
+
+int n;
+pthread_t thdArr[NUM_THREADS];
+pthread_attr_t attr;
+
+void *runner(void *arg)
+{
+    long t = (long)arg;
+    double x, y;
+    long i, count;
+    count = 0;
+    for (i = 0; i < n; ++i)
+    {
+        x = ((double)rand() / RAND_MAX);
+        y = ((double)rand() / RAND_MAX);
+        if (x * x + y * y - 1 <= 0)
+        {
+            ++count;
+        }
+    }
+    pthread_exit((void *)count);
+}
+
+int main(int argc, char *argv[])
+{
+    clock_t t1, t2;
+    srand(time(NULL));
+    int count, rc, nPoints;
+    long t;
+    if (argc != 2)
+    {
+        fprintf(stderr, "usage: pi_multi-thread <integer value>\n");
+        return -1;
+    }
+    nPoints = atoi(argv[1]);
+    if (nPoints <= 0)
+    {
+        fprintf(stderr, "%d must be > 0\n", nPoints);
+        return -1;
+    }
+    n = nPoints / NUM_THREADS;
+    pthread_attr_init(&attr);
+    pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
+    t1 = clock();
+    for (t = 0; t < NUM_THREADS; ++t)
+    {
+        rc = pthread_create(&thdArr[t], &attr, runner, (void *)t);
+        if (rc)
+        {
+            printf("ERROR; return code from pthread_create() is %d\n", rc);
+            exit(-1);
+        }
+    }
+    count = 0;
+    for (t = NUM_THREADS; t >= 0; --t)
+    {
+        void *ret;
+        pthread_join(thdArr[t], &ret);
+        count += (long)ret;
+    }
+    t2 = clock();
+    printf("Time to Execute: %lf\n", (double)(t2 - t1) / CLOCKS_PER_SEC);
+    printf("PI = %lf\n", 4 * (double)count / nPoints);
+    return 0;
+}