c++ udp服务端和客户端设置

在C++中创建UDP（用户数据报协议）服务器和客户端通常涉及以下几个步骤：

**UDP服务器设置**:

1. **包含头文件**:

   #include <iostream>
   #include <string>
   #include <sys/socket.h> // 对于socket操作
   #include <arpa/inet.h>  // 对于地址解析

2. **创建套接字**:

   int server_socket = socket(AF_INET, SOCK_DGRAM, 0);
   if (server_socket == -1) {
       perror("Failed to create socket");
       exit(1);
   }

3. **绑定IP和端口**:

   struct sockaddr_in server_addr;
   server_addr.sin_family = AF_INET;
   server_addr.sin_port = htons(SERV_PORT); // 端口号
   inet_pton(AF_INET, "localhost", &server_addr.sin_addr); // 设置本地IP（这里通常是"localhost"）

   if (bind(server_socket, (struct sockaddr*)&server_addr, sizeof(server_addr)) == -1) {
       perror("Failed to bind");
       close(server_socket);
       exit(1);
   }

4. **接收数据循环**:

   char buffer[BUFSIZ];
   while (true) {
       socklen_t len = sizeof(server_addr);
       ssize_t bytes_received = recvfrom(server_socket, buffer, BUFSIZ, 0, (struct sockaddr*)&client_addr, &len);

       if (bytes_received > 0) {
           std::cout << "Received message from " << inet_ntoa(client_addr.sin_addr) << ":" << ntohs(client_addr.sin_port) << ": " << buffer << "\n";
       } else {
           perror("recvfrom failed");
       }
   }

**UDP客户端设置**:

1. **包含头文件**:
同上

2. **创建套接字**:

   int client_socket = socket(AF_INET, SOCK_DGRAM, 0);
   if (client_socket == -1) {
       perror("Failed to create socket");
       exit(1);
   }

3. **设置发送信息**:

   const char* message = "Hello, Server!";
   struct sockaddr_in server_addr;
   server_addr.sin_family = AF_INET;
   server_addr.sin_port = htons(SERV_PORT);
   inet_pton(AF_INET, "localhost", &server_addr.sin_addr);

   sendto(client_socket, message, strlen(message), 0, (struct sockaddr*)&server_addr, sizeof(server_addr));

4. **关闭套接字**:

   close(client_socket);