/******* 客户端程序 client.c ************/
/********************************************************************************************
**    Name:client.c
**    Used to study the network programming in Linux OS.
**    Showing how to use the functions,
** like socket,bind,listen,accept and write.
**    This is the client program.
**    Author:zeickey
**    Date:2006/9/16        
**    Copyright (c) 2006,All Rights Reserved!
*********************************************************************************************/
#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include <unistd.h>
#include <errno.h>

int main(int argc, char *argv[])
{
    int sockfd;
    char buffer[1024];
    struct sockaddr_in server_addr;
    //struct hostent *host;
    char *ip;
    int portnumber,nbytes;
    
    if(argc!=3)
    {
        fprintf(stderr,"Usage:%s ip portnumber\a\n",argv[0]);
        return 1;
    }
    
    //if((host=gethostbyname(argv[1]))==NULL)
    printf("agrv[1] = %s\n",argv[1]);
    if( strlen(ip=argv[1])< 7 )
    {
        fprintf(stderr,"Get Ip address error\n");
        return 1;
    }
    
    if((portnumber=atoi(argv[2]))<0)
    {
        fprintf(stderr,"Usage:%s hostname portnumber\a\n",argv[0]);
        return 1;
    }
    
    /* 客户程序开始建立 sockfd描述符 */
    if((sockfd=socket(AF_INET,SOCK_STREAM,0))==-1)
    {
        fprintf(stderr,"Socket Error:%s\a\n",strerror(errno));
        return 1;
    }
    
    /* 客户程序填充服务端的资料 */
    bzero(&server_addr, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(portnumber);
    //server_addr.sin_addr = *( (struct in_addr *)host->h_addr );
    //server_addr.sin_addr.s_addr = inet_addr(host->h_addr);
    server_addr.sin_addr.s_addr = inet_addr(ip);
    //server_addr.sin_addr.s_addr = ((struct in_addr*)(host->h_addr))->s_addr;
    
    /* 客户程序发起连接请求 */
    if(connect(sockfd,(struct sockaddr *)(&server_addr),sizeof(struct sockaddr))==-1)
    {
        fprintf(stderr,"Connect Error:%s\a\n",strerror(errno));
        return 1;
    }
    
    /* 连接成功了 */
    if((nbytes=read(sockfd,buffer,1024))==-1)
    {
        fprintf(stderr,"Read Error:%s\n",strerror(errno));
        return 1;
    }
    buffer[nbytes]='\0';
    printf("I have received:%s\n",buffer);
    /* 结束通讯 */
    close(sockfd);
    return 0;
}