用c++写一个udpserver

好的，以下是一个简单的UDP服务器的C代码示例：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#define PORT 8888
#define MAXLINE 1024

int main() {
    int sockfd;
    char buffer[MAXLINE];
    struct sockaddr_in servaddr, cliaddr;

    // 创建socket
    sockfd = socket(AF_INET, SOCK_DGRAM, 0);

    // 绑定地址和端口
    memset(&servaddr, 0, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    servaddr.sin_port = htons(PORT);
    bind(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr));

    printf("UDP server started on port %d\n", PORT);

    while (1) {
        socklen_t len = sizeof(cliaddr);
        int n = recvfrom(sockfd, (char *)buffer, MAXLINE, MSG_WAITALL, (struct sockaddr *)&cliaddr, &len);
        buffer[n] = '\0';
        printf("Received message from %s:%d - %s\n", inet_ntoa(cliaddr.sin_addr), ntohs(cliaddr.sin_port), buffer);
        sendto(sockfd, (const char *)buffer, strlen(buffer), MSG_CONFIRM, (const struct sockaddr *)&cliaddr, len);
    }

    return 0;
}

这个UDP服务器会监听8888端口，接收来自客户端的消息并将其回传。你可以通过修改代码来实现你自己的UDP服务器。