在C语言中使用多线程进行线性搜索

这里我们将看到如何应用多线程概念来搜索数组中的一个元素。这里的方法非常简单。我们将创建一些线程，然后将数组分成不同的部分。不同的线程会在不同的部分进行搜索。之后，当找到该元素时，启用标志来识别该元素。

示例

#include <stdio.h>
#include <pthread.h>
#define MAX 16
#define THREAD_MAX 4
int array[MAX] = { 1, 5, 7, 10, 12, 14, 15, 18, 20, 22, 25, 27, 30, 64, 110, 220 };
int key = 18;
int flag = 0; //flag to indicate that item is found in the array or not
int current_thread = 0;
void* ThreadSearch(void* args) { //This is linear search function. It will be running using all threads
   int num = current_thread++;
   for (int i = num * (MAX / 4); i < ((num + 1) * (MAX / 4)); i++){
      if (array[i] == key)
         flag = 1; //set flag if key is found
   }
}
int main() {
   pthread_t thread[THREAD_MAX];
   for (int i = 0; i < THREAD_MAX; i++) { //create multiple threads
      pthread_create(&thread[i], NULL, ThreadSearch, (void*)NULL);
   }
   for (int i = 0; i < THREAD_MAX; i++) {
      pthread_join(thread[i], NULL); //wait untill all of the threads are completed
   }
   if (flag == 1)
      printf("Key element is found
");
   else
      printf("Key element is not present
");
}

输出

$ gcc 1249.Thread_search.cpp -lpthread
$ ./a.out
Key element is found