自己动手写客户端程序
同样是实现上篇的功能，客户端程序不再用telnet，自己写代码实现，服务器端程序也需要修改下
服务器程序error(char *msg){fprintf(stderr, “%s : %s\n”, msg, strerror(errno) );exit(1);}int open_listener_socket(void){int s = socket(PF_INET, SOCK_STREAM, 0); //创建服务器Socket , Ipv4协议，面向连接通信，，TCP协议if (s == -1)error(“scoket open error”);return s;}void bind_to_port(int socket, int port){struct sockaddr_in name; //服务器网络地址结构体name.sin_family = PF_INET;name.sin_port = (in_port_t)htons(port);// 服务器端口号name.sin_addr.s_addr = htonl(INADDR_ANY); reuse = 1;if ( setsockopt(socket, SOL_SOCKET, SO_REUSEADDR, (char *)&reuse, sizeof(int)) == -1)error(” cant set the reuse option on the scoket”);//将服务器socket绑定到网络地址上int c = bind(socket, (struct sockaddr*) &name, sizeof(name));if (c == -1)error(“cant bind to socket”);}int sent_msg_to_client(int socket, char *s){int result = send(socket, s, strlen(s), 0);if (result == -1)fprintf(stderr, “%s : %s\n”, “error talking to client”, strerror(errno) );return result;}int main(int argc, char const *argv[]){int server_sockfd;int len;server_sockfd = open_listener_socket();bind_to_port(server_sockfd , 30000);// 监听连接请求，监听队列长度为10if (listen(server_sockfd , 10) == -1)error(“cant listen”);address_size = sizeof(client_addr);puts(“waiting for connection”);char buf[255];//等待客户端连接请求到达int client_sockfd = accept(server_sockfd, (struct sockaddr *)&client_addr, &address_size);if (client_sockfd == -1)error(“accept error”);sent_msg_to_client( client_sockfd, “Welcome to my server\n>”);while ((len = recv(client_sockfd, buf, sizeof(buf), 0)) > 0){buf[len] = ‘\0’;printf(“%s\n”, buf);if (strncasecmp(“Who is there?”, buf, 12))sent_msg_to_client(client_sockfd, “You should say ‘Who is there?’ !\r\n>”);else{sent_msg_to_client(client_sockfd, “Oscar\r\n>”);while ((len = recv(client_sockfd, buf, sizeof(buf), 0)) > 0){buf[len] = ‘\0’;printf(“%s\n”, buf);if (strncasecmp(“Oscar who?”, buf, 9)){sent_msg_to_client(client_sockfd, “You should say ‘Oscar who?’ !\r\n>”);continue;}else{sent_msg_to_client(client_sockfd, “Oscar silly question, you get a silly answer\r\n”);break;}}}}return 0;}客户端程序error(char *msg){fprintf(stderr, “%s : %s\n”, msg, strerror(errno) );exit(1);}int open_listener_socket(void){int s = socket(AF_INET, SOCK_STREAM, 0); //创建客户端Socket , Ipv4协议，面向连接通信，TCP协议if (s == -1)error(“scoket open error”);return s;}int main(int argc, char *argv[]){int client_sockfd;char buf[255];int len;struct sockaddr_in client_addr; //客户端网络地址结构体client_addr.sin_family=PF_INET; //设置为IP通信client_addr.sin_addr.s_addr=inet_addr(“127.0.0.1”);//服务器IP地址client_addr.sin_port=htons(30000); //服务器端口号/*创建客户端套接字–IPv4协议，面向连接通信，TCP协议*/client_sockfd= open_listener_socket();/*将套接字绑定到客户端的网络地址上*/if(connect(client_sockfd,(struct sockaddr *)&client_addr,sizeof(struct sockaddr)) == -1){error(“cant connected to server”);}puts(“connected to server\n”);len=recv(client_sockfd,buf,BUFSIZ,0);//接收服务器端信息buf[len]=’\0′;printf(“%s”,buf); //打印服务器端信息while(1){//scanf(“%s”,buf);gets(buf);if(!strcmp(buf,”quit”))break;len=send(client_sockfd,buf,strlen(buf),0);len=recv(client_sockfd,buf,BUFSIZ,0);buf[len]=’\0′;printf(“%s”,buf);}close(client_sockfd);;}
眼睛可以近视，目光不能短浅。
