C/C++网络编程6——实现基于UDP的服务器端/客户端

服务器端：

 #include <iostream>
 #include <arpa/inet.h>
 #include <sys/socket.h>
 #include <unistd.h>
 #include <cstring>

 const unsigned int BUFFER_SIZE = ;

 int main()
 {
     // step1：创建UDP套接字
     int ser_socket = socket(PF_INET, SOCK_DGRAM, );
     if (ser_socket == -) {
         std::cout << "socket failed" << std::endl;
         return ;
     }

     // step2：绑定ip地址和端口号
     sockaddr_in ser_addr;
     memset(&ser_addr, , sizeof(ser_addr));
     ser_addr.sin_family = AF_INET;
     ser_addr.sin_addr.s_addr = htonl(INADDR_ANY);
     ser_addr.sin_port = htons();
     if (bind(ser_socket, (sockaddr *)(&ser_addr), sizeof(ser_addr)) == -) {
         std::cout << "bind failed" << std::endl;
         close(ser_socket);
         return ;
     }

     char message[BUFFER_SIZE];
     sockaddr_in client_addr;
     socklen_t client_addr_len = sizeof(client_addr_len);
     int message_len = recvfrom(ser_socket, message, BUFFER_SIZE, ,
         (sockaddr*)(&client_addr), &client_addr_len);
     std::cout << message << std::endl;

     sendto(ser_socket, message, message_len, ,
         (sockaddr *)(&client_addr), client_addr_len);
     close(ser_socket);
     return ;
 }

客户端：

 #include <iostream>
 #include <arpa/inet.h>
 #include <sys/socket.h>
 #include <unistd.h>
 #include <cstring>

 const unsigned int BUFFER_SIZE = ;

 int main()
 {
     // 创建UDP套接字
     int client_sock = socket(PF_INET, SOCK_DGRAM, );
     if (client_sock == -) {
         std::cout << "socket failed" << std::endl;
         return ;
     }

     sockaddr_in ser_addr;
     memset(&ser_addr, , sizeof(ser_addr));
     ser_addr.sin_family = AF_INET;
     ser_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
     ser_addr.sin_port = htons();

     char info[] = "i love china";
     sendto(client_sock, info, sizeof(info), ,
         (sockaddr *)(&ser_addr), sizeof(ser_addr));

     char message[BUFFER_SIZE];
     sockaddr_in from_addr;
     socklen_t from_addr_len = sizeof(from_addr);
     recvfrom(client_sock, message, BUFFER_SIZE, ,
         (sockaddr*)(&from_addr), &from_addr_len);

     std::cout << message << std::endl;
     close(client_sock);
     return ;
 }