三个线程按顺序打印ABC

た入场券 2023-03-02 07:39 15阅读 0赞

**线程1打印A、线程2打印B、线程3打印C，依次打印十遍（ABCABCABC…）**

#include<pthread.h>
    #include<stdio.h>
    #include<string.h>
    #include<stdlib.h>
    #include<unistd.h>
    #include<semaphore.h>
    
    sem_t sem[3];
    void* task1(void* arg)
    { 
        char* name =(char*)arg;
        while(1)
        { 
            sem_wait(&sem[0]);
            printf("A\n");
            sleep(1);
            sem_post(&sem[1]);
        }
        sem_destroy(&sem[0]);
        pthread_exit(NULL);
    }
    
    void* task2(void* arg)
    { 
        char* name =(char*)arg;
        while(1)
        { 
            sem_wait(&sem[1]);
            printf("B\n");
            sleep(1);
            sem_post(&sem[2]);
        }
        sem_destroy(&sem[1]);
        pthread_exit(NULL);
    }
    
    void* task3(void* arg)
    { 
        char* name =(char*)arg;
        while(1)
        { 
            sem_wait(&sem[2]);
            printf("C\n");
            sleep(1);
            sem_post(&sem[0]);
        }
        sem_destroy(&sem[2]);
        pthread_exit(NULL);
    }
    
    int main()
    { 
        sem_init(&sem[0],0 ,1);
        sem_init(&sem[1],0 ,0);
        sem_init(&sem[2],0 ,0);
    
        pthread_t ptid[3];
        if(pthread_create(&ptid[0],NULL,task1,"friend1")!=0)
        { 
            perror("pthread_create error!");
            exit(1);
        };
    
        if(pthread_create(&ptid[1],NULL,task2,"friend2")!=0)
        { 
            perror("pthread_create error!");
            exit(1);
        }
    
        if(pthread_create(&ptid[2],NULL,task3,"friend2")!=0)
        { 
            perror("pthread_create error!");
            exit(1);
        }
        pthread_exit(NULL);
    }