#include<stdio.h>

#include<sys/types.h>

#include<sys/socket.h>

#include<netinet/in.h>

#include<netdb.h>

#define MAXLINE 4096

 

/*Prints a message when an error occurs and exits*/

 void error(char*);

 

 int main(int argc, char** argv) {

 

 /*This struct is used for geting the name of the server and converting it

   to an IP address using gethostbyname*/

 struct hostent *hp;

 

 /*The socket trough which the server will commmunicate with client*/

 int sockfd;

 

 /*The amount of data received*/

 int n;

 

 /*the date received from the server is stored in recvline*/

 char recvline[MAXLINE+1];

 

 /*the stucture for the address of the Server*/

 struct sockaddr_in servaddr;

 

 /*we have <Executable> <Host Name>*/

 if(argc!=2)

 error("usage: a.out <Host Name>\n");

 

  /* we will store the IP address in hp by converting the host Name*/

  /* if the host name that is given is not valid ==> (hp==Null exit from the

     program*/

 

 if((hp = gethostbyname(argv[1]))==NULL)

    error("host name error");

 

  /*Create the socket */

  /*Verify if it is created ==> (sockfd>0) else print a message and exit*/

  if((sockfd = socket(AF_INET, SOCK_STREAM,0))<0)

  error("unable to open a socket\n");

 

  /*Allocate the space for the address struct*/

  bzero(&servaddr, sizeof(servaddr));

 

  /*Fill the struct*/

  servaddr.sin_family = AF_INET;

  servaddr.sin_port   = htons(13);

 

  /*Copy the IP address from hp to the struct sockaddress*/

  bcopy(hp->h_addr,&servaddr.sin_addr,hp->h_length);

 

  /*Connecting the Host to the Server*/

  /*verify if the connection is established ==> the value returned by

    connect>0 else print message and exit*/

 

  if (connect(sockfd, (struct sockaddr *)&servaddr,sizeof(servaddr))<0)

     error("connect error\n");

 

   /*Read the recvline*/

   while ((n=read(sockfd,recvline,MAXLINE))>0) {

   recvline[n] = 0;

 

   /*print recvline */

   if (fputs(recvline,stdout)==EOF)

    error("fput error\n");

    }

    printf("\n");

    if(n<0) error("read error");

  }

 

 void error (char* str){

    printf("%s",str);

    exit(1);

}