TCP/IP网络编程：理解网络编程和套接字

网络编程又叫做套接字编程，是因为在网络编程中依赖使用套接字(socket),网络编程一般是C/S架构，即客户端/服务器模式，在服务器端依赖套接字绑定自身接口，并开启监听客户端连接，然后进行读写操作；客户端则依赖套接字进行接口连接，以进行收发操作。

服务器端

服务器端遵循以下步骤进行搭建

创建套接字
绑定监听端口
开始监听
接受连接
进行读写操作
关闭连接

下面是创建服务器端通讯的实例

//步骤1：创建套接字int server_sock;server_sock = socket(PF_INET,SOCK_STREAM,0);if (server_sock == -1){error_handing("socket() error");}//步骤2：绑定监听端口struct sockaddr_in server_addr;memset(&server_addr,0,sizeof(server_addr));server_addr.sin_family = AF_INET;server_addr.sin_addr.s_addr = htonl(INADDR_ANY);server_addr.sin_port = htons(atoi("3333"));if (bind(server_sock,(struct sockaddr *)&server_addr,sizeof(server_addr)) == -1){error_handing("bind() error");}//步骤3：开启监听if (listen(server_sock,5) == -1){error_handing("listen() error");}//步骤4：接受连接int accept_sock;struct sockaddr accept_addr;socklen_t len = sizeof(accept_addr);accept_sock = accept(server_sock,&accept_addr,&len);if (accept_sock == -1){error_handing("accept() error");}//步骤5：开始通讯char message[10];if (read(accept_sock,message,10) == -1){error_handing("read() error");}printf("Read message is %s\n",message);if (write(accept_sock,message,10) == -1){error_handing("write() error");}//步骤6：关闭连接close(accept_sock);close(server_sock);

客户端

客户端遵循以下步骤进行搭建

创建套接字
指定端口连接
进行通讯
关闭连接

下面是创建客户端通讯的实例

//步骤1：创建套接字int client_sock;client_sock = socket(PF_INET,SOCK_STREAM,0);if (client_sock == -1){error_handing("socket() error");}//步骤2：连接端口struct sockaddr_in connect_addr;connect_addr.sin_family = AF_INET;connect_addr.sin_addr.s_addr = inet_addr("127.0.0.1");connect_addr.sin_port = htons(3333);if (connect(client_sock,(struct sockaddr *)&connect_addr,sizeof(connect_addr)) == -1){error_handing("connect() error");}//步骤3：进行通讯if (write(client_sock,"nihao",sizeof("nihao")) == -1){error_handing("write() error");}char buffer[30];if (read(client_sock,buffer,30) ==  -1){error_handing("read() error");}printf("Receive message is %s\n",buffer);//步骤4：关闭连接close(client_sock);