网络编程代码实例

最简单的服务器、客户端连接：

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#define PORT 8888


int main()
{
    int sockfd, ret, fd;
    char buf[100] = {0};
    struct sockaddr_in server_addr;
    struct sockaddr_in client_addr;

    printf("Start Server!\n");
    sockfd = socket(PF_INET, SOCK_STREAM, 0);
    if(-1 == sockfd)
    {
        perror("socket");
        exit(1);
    }

    memset(&server_addr, 0 ,sizeof(server_addr));
    server_addr.sin_family = PF_INET;
    server_addr.sin_port = PORT;
    server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    ret = bind(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr));
    if(-1 == ret)
    {
        perror("bind");
        exit(1);
    }

    printf("Listening...\n");
    ret = listen(sockfd,5);
    if(-1 == ret)
    {
        perror("listen");
        exit(1);
    }

    int length = sizeof(client_addr);
    fd = accept(sockfd, (struct sockaddr *)&client_addr, &length);
    if(-1 == fd)
    {
        perror("accept");
        exit(1);
    }

    while(1)
    {
        ret = recv(fd,buf,sizeof(buf),0);
        if(-1 == ret)
        {
            perror("recv");
            exit(1);
        }
        if(!strcmp(buf,"bye"))
        {
            break;
        }
        printf("Recv From Client : %s\n",buf);
        memset(buf, 0, sizeof(buf));
    }

    close(sockfd);
    close(fd);


    return 0;
}

#include 
#include 
#include 
#include 
#include 
#include 
#include 

#define PORT 8888

int main()
{
    int sockfd, ret;
    struct sockaddr_in server_addr;
    char buf[100] = {0};

    sockfd = socket(PF_INET, SOCK_STREAM, 0);
    if(-1 == sockfd)
    {
        perror("socket");
        exit(1);
    }

    memset(&server_addr, 0 ,sizeof(server_addr));
    server_addr.sin_family = PF_INET;
    server_addr.sin_port = PORT;
    server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    printf("Start Connecting...\n");
    ret = connect(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr));
    if(-1 == ret)
    {
        perror("connect");
        exit(1);
    }

    while(1)
    {
        scanf("%s",buf);

        ret = send(sockfd, buf, strlen(buf), 0);
        if(-1 == ret)
        {
            perror("send");
            exit(1);
        }

        if(!strcmp(buf,"bye"))
        {
            break;
        }

        memset(buf, 0, sizeof(buf));
    }

    close(sockfd);
    return 0;
}

建立一个客户端向服务器发信息：

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#define PORT 8888


void *MyReceive(void *arg)
{
    char buf[100] = {0};
    int ret;

    pthread_detach(pthread_self());

    while(1)
    {
        ret = recv(*(int *)arg,buf,sizeof(buf),0);
        if(-1 == ret)
        {
            perror("recv");
            exit(1);
        }
        if(!strcmp(buf,"bye"))
        {
            close(*(int *)arg);
            break;
        }

        printf("Recv From Client %d : %s\n",*(int *)arg,buf);
        memset(buf,0,sizeof(buf));
    }
}

int main()
{
    int fd[100] = {0};
    int length , i = 0;
    int sockfd, ret;
    char buf[100] = {0};
    struct sockaddr_in server_addr;
    struct sockaddr_in client_addr;
    pthread_t tid[100] = {0};

    printf("Start Server!\n");
    sockfd = socket(PF_INET, SOCK_STREAM, 0);
    if(-1 == sockfd)
    {
        perror("socket");
        exit(1);
    }

    memset(&server_addr, 0 ,sizeof(server_addr));
    server_addr.sin_family = PF_INET;
    server_addr.sin_port = PORT;
    server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    ret = bind(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr));
    if(-1 == ret)
    {
        perror("bind");
        exit(1);
    }

    printf("Listening...\n");
    ret = listen(sockfd,5);
    if(-1 == ret)
    {
        perror("listen");
        exit(1);
    }

    while(1)
    {
        length = sizeof(client_addr);
        fd[i] = accept(sockfd, (struct sockaddr *)&client_addr, &length);
        if(-1 == fd[i])
        {
            perror("accept");
            exit(1);
        }

        printf("Accept %d, Port %d\n",fd[i],client_addr.sin_port);

        ret = pthread_create(&tid[i],NULL,MyReceive,(void *)&fd[i]);
        if(0 != ret)
        {
            perror("pthread_create");
            exit(1);
        }
        i++;
    }


    close(sockfd);
    close(fd);


    return 0;
}

#include

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#define PORT 8888

struct info
{
    char buf[100];
    int Tofd;
};

void *MyReceive(void *arg)
{
    struct info Recvbuf = {0};
    int ret;

    pthread_detach(pthread_self());

    while(1)
    {
        ret = recv(*(int *)arg,&Recvbuf,sizeof(Recvbuf),0);
        if(-1 == ret)
        {
            perror("recv");
            exit(1);
        }
      /*  if(!strcmp(buf,"bye"))
        {
            close(*(int *)arg);
            break;
        }

        printf("Recv From Client %d : %s\n",*(int *)arg,buf);*/

        ret = send(Recvbuf.Tofd,&Recvbuf,sizeof(Recvbuf),0);
        if(-1 == ret)
        {
            perror("send");
            exit(1);
        }
        memset(&Recvbuf,0,sizeof(Recvbuf));
    }
}

int main()
{
    int fd[100] = {0};
    int length , i = 0;
    int sockfd, ret;
    char buf[100] = {0};
    struct sockaddr_in server_addr;
    struct sockaddr_in client_addr;
    pthread_t tid[100] = {0};

    printf("Start Server!\n");
    sockfd = socket(PF_INET, SOCK_STREAM, 0);
    if(-1 == sockfd)
    {
        perror("socket");
        exit(1);
    }

    memset(&server_addr, 0 ,sizeof(server_addr));
    server_addr.sin_family = PF_INET;
    server_addr.sin_port = PORT;
    server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    ret = bind(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr));
    if(-1 == ret)
    {
        perror("bind");
        exit(1);
    }

    printf("Listening...\n");
    ret = listen(sockfd,5);
    if(-1 == ret)
    {
        perror("listen");
        exit(1);
    }

    while(1)
    {
        length = sizeof(client_addr);
        fd[i] = accept(sockfd, (struct sockaddr *)&client_addr, &length);
        if(-1 == fd[i])
        {
            perror("accept");
            exit(1);
        }

        printf("Accept %d, Port %d\n",fd[i],client_addr.sin_port);

        ret = pthread_create(&tid[i],NULL,MyReceive,(void *)&fd[i]);
        if(0 != ret)
        {
            perror("pthread_create");
            exit(1);
        }
        i++;
    }


    close(sockfd);
 //   close(fd);


    return 0;
}

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#define PORT 8888

struct info
{
    char buf[100];
    int Tofd;
};

pthread_t tid[2] = {0};

void *Send(void *arg)
{
    struct info Sendbuf = {0};
    int ret;

    while(1)
    {
        scanf("%s%d",Sendbuf.buf,&Sendbuf.Tofd);

        ret = send(*(int *)arg,&Sendbuf, sizeof(Sendbuf), 0);
        if(-1 == ret)
        {
            perror("send");
            exit(1);
        }

        /*if(!strcmp(buf,"bye"))
        {
            break;
        }*/

        memset(&Sendbuf, 0, sizeof(Sendbuf));
    }
}

void *Recv(void *arg)
{
    struct info Recvbuf = {0};
    int ret;

    while(1)
    {
        ret = recv(*(int *)arg,&Recvbuf,sizeof(Recvbuf),0);
        if(-1 == ret)
        {
            perror("recv");
            exit(1);

        }

        printf("\t\t\t%s\n",Recvbuf.buf);

        memset(&Recvbuf,0,sizeof(Recvbuf));
    }
}

int main()
{
    int sockfd, ret;
    struct sockaddr_in server_addr;
   // char buf[100] = {0};

    sockfd = socket(PF_INET, SOCK_STREAM, 0);
    if(-1 == sockfd)
    {
        perror("socket");
        exit(1);
    }

    memset(&server_addr, 0 ,sizeof(server_addr));
    server_addr.sin_family = PF_INET;
    server_addr.sin_port = PORT;
    server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    printf("Start Connecting...\n");
    ret = connect(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr));
    if(-1 == ret)
    {
        perror("connect");
        exit(1);
    }


    ret = pthread_create(&tid[0],NULL,Send,(void *)&sockfd);
    if(0 != ret)
    {
        perror("pthread_create1");
        exit(1);
    }

    ret = pthread_create(&tid[1],NULL,Recv,(void *)&sockfd);
    if(0 != ret)
    {
        perror("pthread_create2");
        exit(1);
    }

    pthread_join(tid[0],NULL);
    pthread_join(tid[1],NULL);
    close(sockfd);
    return 0;
}

用多线程实现上述功能：

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#define PORT   8888

struct info 
{
    int ToFd;
    char buf[100];
};

void *MyReceive(void *arg)
{
    struct info RecvBuf = {0};
    int ret;

    pthread_detach(pthread_self());

    while (1)
    {
        ret = recv(*(int *)arg, &RecvBuf, sizeof(RecvBuf), 0);
        if (-1 == ret)
        {
            perror("recv");
            exit(1);
        }
        if (!strcmp(RecvBuf.buf, "bye"))
        {
            close(*(int *)arg);
            break;
        }
        //printf("Recv From Client %d : %s\n", *(int *)arg, buf);

        ret = send(RecvBuf.ToFd, &RecvBuf, sizeof(RecvBuf), 0);
        if (-1 == ret)
        {
            perror("send");
            exit(1);
        }

        memset(&RecvBuf, 0, sizeof(RecvBuf));
    }
}

int main()
{
    int sockfd, ret, fd[100] = {0}, length, i = 0;
    char buf[100] = {0};
    struct sockaddr_in server_addr;
    struct sockaddr_in client_addr;
    pthread_t tid[100] = {0};

    printf("Start Server!\n");
    sockfd = socket(PF_INET, SOCK_STREAM, 0);
    if (-1 == sockfd)
    {
        perror("socket");
        exit(1);
    }

    int opt = 1;
    setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));

    memset(&server_addr, 0, sizeof(server_addr));
    server_addr.sin_family = PF_INET;
    server_addr.sin_port = PORT;
    server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    ret = bind(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr));
    if (-1 == ret)
    {
        perror("bind");
        exit(1);
    }

    printf("Listening...\n");
    ret = listen(sockfd, 5);
    if(-1 == ret)
    {
        perror("listen");
        exit(1);
    }

    while (1)
    {
        length = sizeof(client_addr);
        fd[i] = accept(sockfd, (struct sockaddr *)&client_addr, &length);
        if (-1 == fd[i])
        {
            perror("accept");
            exit(1);
        }

        printf("Accept %d , Port %d\n", fd[i], client_addr.sin_port);

        ret = pthread_create(&tid[i], NULL, MyReceive, (void *)&fd[i]);
        if (0 != ret)
        {
            perror("pthread_create");
            exit(1);
        }
        i++;
    }

    close(sockfd);

    return 0;
}

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#define PORT    8888

struct info
{
    int ToFd;
    char buf[100];
};

pthread_t tid[2] = {0};

void *Send(void *arg)
{
    struct info SendBuf = {0};
    int ret;

    while (1)
    {
        scanf("%s %d", SendBuf.buf, &SendBuf.ToFd);

        ret = send(*(int *)arg, &SendBuf, sizeof(SendBuf), 0);
        if (-1 == ret)
        {
            perror("send");
            exit(1);
        }

        if (!strcmp(SendBuf.buf, "bye"))
        {
            close(*(int *)arg);
            pthread_cancel(tid[1]);
            break;
        }

        memset(&SendBuf, 0, sizeof(SendBuf));
    }

}

void *Recv(void *arg)
{
    struct info RecvBuf = {0};
    int ret, oldtype;

    pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, &oldtype);

    while (1)
    {
        ret = recv(*(int *)arg, &RecvBuf, sizeof(RecvBuf), 0);
        if (-1 == ret)
        {
            perror("recv");
            exit(1);
        }

        printf("\t\t\t%s\n", RecvBuf.buf);

        memset(&RecvBuf, 0, sizeof(RecvBuf));
    }
}

int main()
{
    int sockfd, ret;
    struct sockaddr_in server_addr;

    sockfd = socket(PF_INET, SOCK_STREAM, 0);
    if (-1 == sockfd)
    {
        perror("socket");
        exit(1);
    }

    memset(&server_addr, 0, sizeof(server_addr));
    server_addr.sin_family = PF_INET;
    server_addr.sin_port = PORT;
    server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    printf("Start Connecting...\n");
    ret = connect(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr));
    if (-1 == ret)
    {
        perror("connect");
        exit(1);
    }

    ret = pthread_create(&tid[0], NULL, Send, (void *)&sockfd);
    if (0 != ret)
    {
        perror("pthread_create1");
        exit(1);
    }

    ret = pthread_create(&tid[1], NULL, Recv, (void *)&sockfd);
    if (0 != ret)
    {
        perror("pthread_create2");
        exit(1);
    }

    pthread_join(tid[0], NULL);
    pthread_join(tid[1], NULL);

    close(sockfd);

    return 0;
}

上述程序修改版：

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#define PORT   8888

struct info 
{
    int ToFd;
    char buf[100];
};


int main()
{
    int sockfd, ret, fd[100] = {0}, length, i = 0, j;
    struct sockaddr_in server_addr;
    struct sockaddr_in client_addr;
    fd_set ReadFd, TmpFd;
    int MaxFd;
    struct info RecvBuf;

    printf("Start Server!\n");
    sockfd = socket(PF_INET, SOCK_STREAM, 0);
    if (-1 == sockfd)
    {
        perror("socket");
        exit(1);
    }

    int opt = 1;
    setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));

    bzero(&server_addr, sizeof(server_addr));
    server_addr.sin_family = PF_INET;
    server_addr.sin_port =htons(PORT);
    server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    ret = bind(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr));
    if (-1 == ret)
    {
        perror("bind");
        exit(1);
    }

    ret = listen(sockfd, 5);
    if(-1 == ret)
    {
        perror("listen");
        exit(1);
    }

    FD_ZERO(&ReadFd);
    FD_ZERO(&TmpFd);
    FD_SET(sockfd,&ReadFd);
    MaxFd = sockfd;

    while(1)
    {
        TmpFd = ReadFd;
        ret = select(MaxFd + 1, &TmpFd, NULL, NULL, NULL);
        if(-1 == ret)
        {
            perror("select");
            exit(1);
        }

        if(FD_ISSET(sockfd,&TmpFd))
        {
            length = sizeof(client_addr);
            fd[i] = accept(sockfd, (struct sockaddr *)&client_addr, &length);
            if (-1 == fd[i])
            {
                perror("accept");
                exit(1);
            }

            printf("Accept %d , Port %d\n", fd[i], client_addr.sin_port);

            FD_SET(fd[i],&ReadFd);
            MaxFd = fd[i];
            i++;
        }
        else
        {
            for(j = 0; j < i; i++)
            {
                if(FD_ISSET(fd[j],&TmpFd))
                {
                    ret = recv(fd[j],&RecvBuf,sizeof(RecvBuf),0);
                    if(ret < 0)
                    {
                        perror("recv");
                        exit(1);
                    }

                    ret = send(RecvBuf.ToFd,&RecvBuf,sizeof(RecvBuf),0);
                    if(ret < 0)
                    {
                        perror("send");
                        exit(1);
                    }
                }
            }
        }
    }



    return 0;
}

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#define PORT    8888

struct info
{
    int ToFd;
    char buf[100];
};

pthread_t tid[2] = {0};

void *Send(void *arg)
{
    struct info SendBuf = {0};
    int ret;

    while (1)
    {
        scanf("%s %d", SendBuf.buf, &SendBuf.ToFd);

        ret = send(*(int *)arg, &SendBuf, sizeof(SendBuf), 0);
        if (-1 == ret)
        {
            perror("send");
            exit(1);
        }

        if (!strcmp(SendBuf.buf, "bye"))
        {
            close(*(int *)arg);
            pthread_cancel(tid[1]);
            break;
        }

        memset(&SendBuf, 0, sizeof(SendBuf));
    }

}

void *Recv(void *arg)
{
    struct info RecvBuf = {0};
    int ret, oldtype;

    pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, &oldtype);

    while (1)
    {
        ret = recv(*(int *)arg, &RecvBuf, sizeof(RecvBuf), 0);
        if (-1 == ret)
        {
            perror("recv");
            exit(1);
        }

        printf("\t\t\t%s\n", RecvBuf.buf);

        memset(&RecvBuf, 0, sizeof(RecvBuf));
    }
}

int main()
{
    int sockfd, ret;
    struct sockaddr_in server_addr;

    sockfd = socket(PF_INET, SOCK_STREAM, 0);
    if (-1 == sockfd)
    {
        perror("socket");
        exit(1);
    }

    memset(&server_addr, 0, sizeof(server_addr));
    server_addr.sin_family = PF_INET;
    server_addr.sin_port = htons(PORT);
    server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    printf("Start Connecting...\n");
    ret = connect(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr));
    if (-1 == ret)
    {
        perror("connect");
        exit(1);
    }

    ret = pthread_create(&tid[0], NULL, Send, (void *)&sockfd);
    if (0 != ret)
    {
        perror("pthread_create1");
        exit(1);
    }

    ret = pthread_create(&tid[1], NULL, Recv, (void *)&sockfd);
    if (0 != ret)
    {
        perror("pthread_create2");
        exit(1);
    }

    pthread_join(tid[0], NULL);
    pthread_join(tid[1], NULL);

    close(sockfd);

    return 0;
}