C语言多线程影剧院模拟程序

以下是一个简单的C语言多线程影剧院模拟程序，它可以模拟影院售票和退票的过程：

#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>

#define NUM_SEATS 50 // 影厅座位数
#define NUM_THREADS 20 // 售票员和退票员数量

int num_tickets_sold = 0; // 已售票数
int num_tickets_refunded = 0; // 已退票数
int num_seats_available = NUM_SEATS; // 剩余座位数
pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER; // 互斥锁

void *sell_tickets(void *arg) {
    int num_tickets = rand() % 4 + 1; // 随机售票数量
    pthread_mutex_lock(&mutex); // 加锁
    if (num_seats_available >= num_tickets) { // 如果有足够的座位
        num_seats_available -= num_tickets; // 更新座位数
        num_tickets_sold += num_tickets; // 更新售票数
        printf("%d tickets sold by thread %ld\n", num_tickets, pthread_self());
    } else {
        printf("Not enough seats available for thread %ld\n", pthread_self());
    }
    pthread_mutex_unlock(&mutex); // 解锁
    pthread_exit(NULL);
}

void *refund_tickets(void *arg) {
    int num_tickets = rand() % 2 + 1; // 随机退票数量
    pthread_mutex_lock(&mutex); // 加锁
    if (num_tickets_sold >= num_tickets) { // 如果有足够的已售票数
        num_seats_available += num_tickets; // 更新座位数
        num_tickets_sold -= num_tickets; // 更新售票数
        num_tickets_refunded += num_tickets; // 更新退票数
        printf("%d tickets refunded by thread %ld\n", num_tickets, pthread_self());
    } else {
        printf("Not enough tickets sold for thread %ld\n", pthread_self());
    }
    pthread_mutex_unlock(&mutex); // 解锁
    pthread_exit(NULL);
}

int main() {
    pthread_t threads[NUM_THREADS];
    int i;
    for (i = 0; i < NUM_THREADS; i++) {
        if (i % 2 == 0) { // 偶数线程为售票员
            pthread_create(&threads[i], NULL, sell_tickets, NULL);
        } else { // 奇数线程为退票员
            pthread_create(&threads[i], NULL, refund_tickets, NULL);
        }
    }
    for (i = 0; i < NUM_THREADS; i++) {
        pthread_join(threads[i], NULL);
    }
    printf("Total tickets sold: %d\n", num_tickets_sold);
    printf("Total tickets refunded: %d\n", num_tickets_refunded);
    printf("Remaining seats: %d\n", num_seats_available);
    return 0;
}