initial commit

main.c

@@ -0,0 +1,86 @@
+#include <stdio.h>
+#include <pthread.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+bool is_prime(const int n) {
+    for (int i = 2; i < n; i++) {
+        if (n % i == 0) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
+void* aThread(void *ptr) {
+    const int *arr = (int *)ptr;
+    //printf("%d, %d\n", arr[0], arr[1]);
+    const int r = arr[1]-arr[0];
+    int *n = malloc(r * sizeof(int));
+    if (n == nullptr) perror("fail");
+    memset(n, 0, r);
+    int c = 0;
+
+    for (int i = arr[0]; i < arr[1]; i++) {
+        if (is_prime(i)) {
+            n[c] = i;
+            c++;
+        }
+    }
+
+    n[c+1] = -1;
+
+    return n;
+}
+
+int get_threads() {
+    const int num_cores = (int)sysconf(_SC_NPROCESSORS_ONLN); // Logical cores online
+    if (num_cores == -1) {
+        perror("sysconf");
+        exit(EXIT_FAILURE);
+    }
+
+    return num_cores;
+}
+
+int main(void) {
+    const int thr_num = get_threads();
+    constexpr int max_prime = 2000000;
+    const int slice = max_prime / thr_num;
+    pthread_t thread_id[thr_num];
+
+    int start = 2;
+
+    for (int i = 0; i < thr_num; i++) {
+        int *arr = malloc(2 * sizeof(int));
+        if (arr == nullptr) perror("Failed!");
+        memset(arr, 0, 2);
+        arr[0] = start;
+        arr[1] = (start + slice) > max_prime ? max_prime : start + slice;
+
+        pthread_create(&thread_id[i], nullptr, aThread, arr);
+        start = arr[1];
+    }
+
+    int c = 0;
+
+    for (int i = 0; i < thr_num; i++) {
+        void *thread_res = nullptr;
+        pthread_join(thread_id[i], &thread_res);
+        int *result = (int *)thread_res;
+        int prime = 0;
+
+        for (int t = 0;; t++) {
+            prime = result[t];
+            if (prime == -1 || prime == 0) break;
+            printf("%d\n", prime);
+            c++;
+        }
+    }
+
+    printf("Together %d.", c);
+
+    exit(EXIT_SUCCESS);
+}