//https://blog.csdn.net/xiongping_/article/details/47722049

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>

#define PORT 45454
#define MAXDATASIZE 100

int main(int argc, char *argv[])
{
    int sockfd, num;
    char buf[MAXDATASIZE];

    struct hostent *he;
    struct sockaddr_in server,peer;

    if (argc !=3)
    {
        printf("Usage: %s <IP Address><message>\n",argv[0]);
        exit(1);
    }

    if ((he=gethostbyname(argv[1]))==NULL)
    {
        printf("gethostbyname()error\n");
        exit(1);
    }

    // if ((he=gethostbyname("127.0.0.1"))==NULL)
    // {
    //     printf("gethostbyname()error\n");
    //     exit(1);
    // }

    if ((sockfd=socket(AF_INET, SOCK_DGRAM,0))==-1)
    {
        printf("socket() error\n");
        exit(1);
    }

    bzero(&server,sizeof(server));
    server.sin_family = AF_INET;
    server.sin_port = htons(PORT);
    server.sin_addr= *((struct in_addr *)he->h_addr);

    sendto(sockfd, argv[2],strlen(argv[2]),0,(struct sockaddr *)&server,sizeof(server));

//    socklen_t  addrlen;
//    addrlen=sizeof(server);
//    while (1)
//    {
//        if((num=recvfrom(sockfd,buf,MAXDATASIZE,0,(struct sockaddr *)&peer,&addrlen))== -1)
//        {
//            printf("recvfrom() error\n");
//            exit(1);
//        }
//        if (addrlen != sizeof(server) ||memcmp((const void *)&server, (const void *)&peer,addrlen) != 0)
//        {
//            printf("Receive message from otherserver.\n");
//            continue;
//        }
//
//        buf[num]='\0';
//        printf("Server Message:%s\n",buf);
//        break;
//    }

    close(sockfd);
}