用C语言实现DNS域名解析通过UDP实现client端与localserver通信，请帮我实现client端

好的，以下是一个简单的用C语言实现DNS域名解析通过UDP实现client端与localserver通信的例子代码：

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

#define SERVER "127.0.0.1"  // localserver地址
#define BUFLEN 512  // 缓冲区长度
#define PORT 53  // DNS服务器端口号

void error(const char *msg) {
    perror(msg);
    exit(1);
}

int main(int argc, char **argv) {
    struct sockaddr_in si_other;  // server地址
    int s, slen = sizeof(si_other), i;
    char buf[BUFLEN];

    if (argc < 2) {
        printf("Usage: %s <hostname>\n", argv[0]);
        return 0;
    }

    // 创建socket
    if ((s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1) {
        error("socket");
    }

    // 设置server地址
    memset((char *) &si_other, 0, sizeof(si_other));
    si_other.sin_family = AF_INET;
    si_other.sin_port = htons(PORT);
    if (inet_aton(SERVER, &si_other.sin_addr) == 0) {
        fprintf(stderr, "inet_aton() failed\n");
        exit(1);
    }

    // 构造DNS请求报文
    char hostname[100];
    strcpy(hostname, argv[1]);
    for (i = 0; i < strlen(hostname); i++) {
        if (hostname[i] == '.') {
            hostname[i] = i - (i > 0 ? 1 : 0);
        }
    }
    int len = strlen(hostname) + 1;
    char dns_query[len + 16];
    memset(dns_query, 0, len + 16);
    dns_query[1] = 1;
    dns_query[len + 15] = 1;
    for (i = 0; i < len; i++) {
        dns_query[i + 12] = hostname[i];
    }

    // 发送请求报文
    if (sendto(s, dns_query, len + 16, 0, (struct sockaddr *) &si_other, slen) == -1) {
        error("sendto");
    }

    // 接收响应报文
    if (recvfrom(s, buf, BUFLEN, 0, (struct sockaddr *) &si_other, &slen) == -1) {
        error("recvfrom");
    }

    // 解析响应报文
    int answer_len = ntohs(*(unsigned short *)(buf + 6)) + 12;
    char answer[answer_len];
    memcpy(answer, buf, answer_len);
    struct sockaddr_in addr;
    memcpy(&addr.sin_addr, answer + answer_len - 4, 4);
    printf("%s: %s\n", argv[1], inet_ntoa(addr.sin_addr));

    close(s);
    return 0;
}

该例子通过构造DNS请求报文，发送UDP数据包到localserver，接收localserver返回的响应报文，并解析出IP地址。

注意：该例子只适用于IPv4地址解析。