【Linux】巧妙运用＜信号量＞解决＜水果放取问题＞（思维导图＆代码演示＆思路解析）

https://www.php.cn/link/93ac0c50dd620dc7b88e5fe05c70e15binclude <stdio.h>
https://www.php.cn/link/93ac0c50dd620dc7b88e5fe05c70e15binclude <stdlib.h>
https://www.php.cn/link/93ac0c50dd620dc7b88e5fe05c70e15binclude <pthread.h>
https://www.php.cn/link/93ac0c50dd620dc7b88e5fe05c70e15binclude <semaphore.h>
https://www.php.cn/link/93ac0c50dd620dc7b88e5fe05c70e15binclude <unistd.h>

https://www.php.cn/link/93ac0c50dd620dc7b88e5fe05c70e15bdefine APPLE 1
https://www.php.cn/link/93ac0c50dd620dc7b88e5fe05c70e15bdefine ORANGE 2

// 表示放入水果
int fruitOnPlate = 0;
int fruitType = 0;

// 设置信号量
sem_t plate, appleReady, orangeReady;

void *father(void *arg) {
    while (1) {
        sem_wait(&plate);
        fruitOnPlate = 1;
        fruitType = APPLE;  // 放入苹果
        printf("Father put an apple.\n");
        sem_post(&appleReady);
        sleep(rand() % 10); // 睡眠随机时间
    }
}

void *mother(void *arg) {
    while (1) {
        sem_wait(&plate);
        fruitOnPlate = 1;
        fruitType = ORANGE;  // 放入橘子
        printf("Mother put an orange.\n");
        sem_post(&orangeReady);
        sleep(rand() % 10); // 睡眠随机时间
    }
}

void *son(void *arg) {
    while (1) {
        sem_wait(&orangeReady); // 等待橘子
        if (fruitType == ORANGE) {
            printf("Son ate an orange.\n");
            sem_post(&plate);
        }
    }
}

void *daughter(void *arg) {
    while (1) {
        sem_wait(&appleReady); // 等待苹果
        if (fruitType == APPLE) {
            printf("Daughter ate an apple.\n");
            sem_post(&plate);
        }
    }
}

int main() {
    pthread_t f_thread, m_thread, son_thread, dau_thread;

    sem_init(&plate, 0, 1);
    sem_init(&appleReady, 0, 0);
    sem_init(&orangeReady, 0, 0);

    pthread_create(&f_thread, NULL, father, NULL);
    pthread_create(&m_thread, NULL, mother, NULL);
    pthread_create(&son_thread, NULL, son, NULL);
    pthread_create(&dau_thread, NULL, daughter, NULL);

    pthread_join(f_thread, NULL);
    pthread_join(m_thread, NULL);
    pthread_join(son_thread, NULL);
    pthread_join(dau_thread, NULL);

    sem_destroy(&plate);
    sem_destroy(&appleReady);
    sem_destroy(&orangeReady);

    return 0;
}