linux下 socket的多人聊天室

用socket实现一个多人聊天室的思路很简单，即在服务器端定义一个fd的int型数组，用来存储已经连接的客户端的socket连接套接字fd（因为发送和接收数据都只需要借助连接套接字fd），当服务器接收到来自某一客户端的数据时，直接转发给其他所有连接着的客户端，即完成了多人聊天室。
服务器端：多线程进行数据的转发
客户端：创建一个线程专门用来接收数据，主线程进行输入数据等操作
下面直接贴代码：
server.c

    #include <stdio.h> 
    #include <strings.h> 
    #include <unistd.h> 
    #include <sys/types.h> 
    #include <sys/socket.h> 
    #include <netinet/in.h> 
    #include <arpa/inet.h>
    #include<pthread.h> 
    #include<stdlib.h>

    #define PORT 1234 
    #define BACKLOG 1 
    #define Max 5
    #define MAXSIZE 1024

/*定义全局变量*/
int fdt[Max]={0};
char mes[1024];

/**/

void *pthread_service(void* sfd)
{
    int fd=*(int *)sfd;
    while(1)
    {
        int numbytes;
        int i;
        numbytes=recv(fd,mes,MAXSIZE,0);
        if(numbytes<=0){
            for(i=0;i<Max;i++){
                if(fd==fdt[i]){
                    fdt[i]=0;               
                }
            }
            printf("numbytes=%d\n",numbytes);
            printf("exit! fd=%d\n",fd);
            break;

        }
        printf("receive message from %d,size=%d\n",fd,numbytes);
        SendToClient(fd,mes,numbytes);
        bzero(mes,MAXSIZE);

    }
    close(fd);

}


/**/
int SendToClient(int fd,char* buf,int Size)
{
    int i;
    for(i=0;i<Max;i++){
        printf("fdt[%d]=%d\n",i,fdt[i]);
        if((fdt[i]!=0)&&(fdt[i]!=fd)){
            send(fdt[i],buf,Size,0); 
            printf("send message to %d\n",fdt[i]);
        }
    }   
    return 0;


}

int  main()  
{ 


    int listenfd, connectfd;    
    struct sockaddr_in server; 
    struct sockaddr_in client;      
    int sin_size; 
    sin_size=sizeof(struct sockaddr_in); 
    int number=0;
    int fd;


    if ((listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) 
    {   
        perror("Creating socket failed.");
        exit(1);
    }


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

    bzero(&server,sizeof(server));  


    server.sin_family=AF_INET; 
    server.sin_port=htons(PORT); 
    server.sin_addr.s_addr = htonl (INADDR_ANY); 


    if (bind(listenfd, (struct sockaddr *)&server, sizeof(struct sockaddr)) == -1) { 
    perror("Bind error.");
    exit(1); 
    }   


    if(listen(listenfd,BACKLOG) == -1){  
    perror("listen() error\n"); 
    exit(1); 
    } 
    printf("Waiting for client....\n");


    while(1)
    {

        if ((fd = accept(listenfd,(struct sockaddr *)&client,&sin_size))==-1) {
        perror("accept() error\n"); 
        exit(1); 

        }

        if(number>=Max){
            printf("no more client is allowed\n");
            close(fd);
        }

        int i;
        for(i=0;i<Max;i++){
            if(fdt[i]==0){
                fdt[i]=fd;
                break;
            }

        }



        pthread_t tid;
        pthread_create(&tid,NULL,(void*)pthread_service,&fd);

        number=number+1;


    }


    close(listenfd);            
    }

client.c

    #include <stdio.h> 
    #include <stdlib.h> 
    #include <unistd.h>
    #include <strings.h>
    #include <sys/types.h> 
    #include <sys/socket.h> 
    #include <netinet/in.h> 
    #include <netdb.h> 
    #include<string.h>

    #define PORT 1234 
    #define MAXDATASIZE 100 

    char sendbuf[1024];
    char recvbuf[1024];
    char name[100];
    int fd;

    void pthread_recv(void* ptr)
{
    while(1)
    {
    if ((recv(fd,recvbuf,MAXDATASIZE,0)) == -1){ 
        printf("recv() error\n"); 
        exit(1); 
        } 
    printf("%s",recvbuf);
    memset(recvbuf,0,sizeof(recvbuf));
    }
}



    int main(int argc, char *argv[]) 
    { 
    int  numbytes;   
    char buf[MAXDATASIZE];   
    struct hostent *he;       
    struct sockaddr_in server;  


    if (argc !=2) {         printf("Usage: %s <IP Address>\n",argv[0]); 
    exit(1); 
    } 


    if ((he=gethostbyname(argv[1]))==NULL){  
    printf("gethostbyname() error\n"); 
    exit(1); 
    } 

    if ((fd=socket(AF_INET, SOCK_STREAM, 0))==-1){ 
    printf("socket() error\n"); 
    exit(1); 
    } 

    bzero(&server,sizeof(server));

    server.sin_family = AF_INET; 
    server.sin_port = htons(PORT); 
    server.sin_addr = *((struct in_addr *)he->h_addr);  
    if(connect(fd, (struct sockaddr *)&server,sizeof(struct sockaddr))==-1){  
    printf("connect() error\n"); 
    exit(1); 
    } 

    printf("connect success\n");
    char str[]="已进入聊天室\n";
    printf("请输入用户名：");
    fgets(name,sizeof(name),stdin);
    send(fd,name,(strlen(name)-1),0);
    send(fd,str,(strlen(str)),0);


    pthread_t tid;
    pthread_create(&tid,NULL,pthread_recv,NULL);

    while(1)
    {
        memset(sendbuf,0,sizeof(sendbuf));
        fgets(sendbuf,sizeof(sendbuf),stdin);
        if(strcmp(sendbuf,"exit")==0){
            memset(sendbuf,0,sizeof(sendbuf));
            printf("您已退出群聊\n");
            send(fd,sendbuf,(strlen(sendbuf)),0);
            break;
        }
        send(fd,name,(strlen(name)-1),0);
        send(fd,":",1,0);

        send(fd,sendbuf,(strlen(sendbuf)),0);


    }
// sprintf("")
// if ((numbytes=recv(fd,buf,MAXDATASIZE,0)) == -1){ 
 // printf("recv() error\n"); 
 // exit(1); 
 // } 

    close(fd);  
 }

下面是程序运行截图：