threadlab finished

threadlab/SearchRandom-pthread.c

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+#include <stdio.h>
+#include <time.h>
+#include <pthread.h>
+#include <unistd.h> // For sysconf
+
+// 随机数更新函数 (与原版相同)
+void GenerateRandomNumber(unsigned int *rand1_h, unsigned int *rand1_l) {
+    unsigned long long x = (unsigned long long)*rand1_h;
+    x *= 0x6AC690C5;
+    x += *rand1_l;
+    *rand1_h = (unsigned int)x;
+    *rand1_l = (unsigned int)(x >> 32);
+}
+
+// 定义传递给线程的参数结构体
+typedef struct {
+    unsigned int start;
+    unsigned int end;
+    unsigned int search_val;
+} ThreadArgs;
+
+// 全局互斥锁，只用于保护printf函数，防止输出混乱
+pthread_mutex_t printf_mutex = PTHREAD_MUTEX_INITIALIZER;
+
+// 线程执行的函数
+void* search_worker(void* args) {
+    ThreadArgs* t_args = (ThreadArgs*)args;
+    unsigned int begin_h = t_args->end;
+    unsigned int begin_l = t_args->start;
+    unsigned int search_val = t_args->search_val;
+
+    // *** 核心改动：不再提前退出，每个线程必须完成自己的任务 ***
+    for (unsigned int i = begin_l; i < begin_h; ++i) {
+        unsigned int h = i;
+        unsigned int l = 0x29A;
+        GenerateRandomNumber(&h, &l);
+        GenerateRandomNumber(&h, &l);
+
+        if (l == search_val) {
+            // 找到结果，锁住互斥锁以安全地打印
+            pthread_mutex_lock(&printf_mutex);
+            printf("找到啦~! 密码是 %08X (由线程 %lu 找到)\n", i, pthread_self());
+            pthread_mutex_unlock(&printf_mutex);
+            // *** 核心改动：不再退出，继续搜索本线程范围内的其他可能解 ***
+        }
+    }
+    pthread_exit(NULL);
+}
+
+int main() {
+    time_t begin_time, end_time;
+    const unsigned int search_val = 0x39A6FFBB;
+    
+    // 注意：原程序的循环条件是 i < 0xFFFFFFFF，所以它本身不会测试 0xFFFFFFFF
+    // 为了保持行为一致，我们将总范围设为 0xFFFFFFFF
+    const unsigned long long total_range_end = 0xFFFFFFFF;
+
+    long num_threads = sysconf(_SC_NPROCESSORS_ONLN);
+    if (num_threads <= 0) {
+        num_threads = 4; // 默认值
+    }
+    printf("这是一个修正后的Pthreads并行搜索程序，将使用 %ld 个线程。\n", num_threads);
+
+    begin_time = time(NULL);
+
+    pthread_t threads[num_threads];
+    ThreadArgs thread_args[num_threads];
+    
+    // 注意数据类型，防止溢出
+    unsigned long long chunk_size = total_range_end / num_threads;
+
+    for (long i = 0; i < num_threads; ++i) {
+        thread_args[i].start = i * chunk_size;
+        // 最后一个线程负责处理余下的所有范围
+        thread_args[i].end = (i == num_threads - 1) ? total_range_end : (i + 1) * chunk_size;
+        thread_args[i].search_val = search_val;
+
+        if (pthread_create(&threads[i], NULL, search_worker, &thread_args[i]) != 0) {
+            perror("Failed to create thread");
+            return 1;
+        }
+    }
+
+    // 等待所有线程完成
+    for (long i = 0; i < num_threads; ++i) {
+        if (pthread_join(threads[i], NULL) != 0) {
+            perror("Failed to join thread");
+            return 2;
+        }
+    }
+
+    end_time = time(NULL);
+    printf("耗时 %ld 秒~~\n", end_time - begin_time);
+
+    return 0;
+}
+