c++ 创建及发送udp socket代码

很好，以下是在C语言中创建及发送UDP socket的示例代码：

#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];
    char *hello = "Hello from client";
    struct sockaddr_in servaddr;

    // create socket
    if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
        perror("socket creation failed");
        exit(EXIT_FAILURE);
    }

    memset(&servaddr, 0, sizeof(servaddr));

    // assign IP, PORT
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = INADDR_ANY;
    servaddr.sin_port = htons(PORT);

    // send message to server
    int n, len;
    sendto(sockfd, (const char *)hello, strlen(hello), MSG_CONFIRM, (const struct sockaddr *)&servaddr, sizeof(servaddr));
    printf("Hello message sent from client\n");

    // receive message from server
    n = recvfrom(sockfd, (char *)buffer, MAXLINE, MSG_WAITALL, (struct sockaddr *)&servaddr, &len);
    buffer[n] = '\0';
    printf("Message received from server: %s\n", buffer);

    close(sockfd);
    return 0;
}

以上代码创建了一个UDP socket并向服务器发送了一条消息。你可以根据自己的需要修改代码中的IP地址、端口号和消息内容。