96 lines
2.0 KiB
C
96 lines
2.0 KiB
C
/*
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编写一个程序, 创建多个线程, 每个线程负责对一个共享链表进行搜索操作。要求实现线程间的同步, 确保每个线程搜索链表时不会干扰其他线程的工作。
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*/
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#include <stdio.h>
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#include <pthread.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <string.h>
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pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
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typedef struct node
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{
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char name[32];
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struct node *next;
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} Node;
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Node *head; // 定义头节点
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void *find(void *data)
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{
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int n = 0; // 标识待查询内容在链表中的索引号
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char *name = (char *)data;
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pthread_mutex_lock(&mutex);
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// 查询
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Node *p = head->next;
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while (p != NULL)
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{
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if (strcmp(p->name, name) == 0)
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{
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printf("%s 在链表的索引为 %d\n", name, n);
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pthread_mutex_unlock(&mutex);
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return NULL;
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}
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n++;
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p = p->next;
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}
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printf("%s 在链表中未找到\n", name);
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pthread_mutex_unlock(&mutex);
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return NULL;
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}
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// 添加节点
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void add_node(Node *head, char *name)
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{
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Node *p = head;
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while (p->next != NULL)
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p = p->next;
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Node *new_node = (Node *)malloc(sizeof(Node));
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if (NULL == new_node)
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{
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perror("malloc error");
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return;
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}
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memset(new_node, 0, sizeof(Node)); // 初始化新节点为默认值
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strcpy(new_node->name, name);
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p->next = new_node;
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}
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int main(int argc, char const *argv[])
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{
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head = (Node *)malloc(sizeof(Node));
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if (NULL == head)
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{
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perror("malloc error");
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return 1;
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}
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memset(head, 0, sizeof(Node));
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add_node(head, "a");
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add_node(head, "b");
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add_node(head, "c");
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add_node(head, "d");
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// 待查询字符表，包含查询的字符顺序
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char *alphabet[4] = {"a", "e", "d", "b"};
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pthread_t t[4];
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for (int i = 0; i < 4; i++)
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{
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pthread_create(&t[i], NULL, find, (void *)alphabet[i]);
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}
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for (int i = 0; i < 4; i++)
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{
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pthread_join(t[i], NULL);
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}
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pthread_mutex_destroy(&mutex);
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return 0;
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}
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