/*
   tcp-c1.c: illustrates a TCP client
*/

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


void int_handler(int dummy)
{
   printf("Write error to socket... exiting....\n");
   fflush(stdout);
   exit(1);
}

int main(int argc, char *argv[])
{
   int s;				/* s = socket */
   struct sockaddr_in server;		/* Server's Internet address */
   struct hostent *host_entry_ptr;	/* Translate hostname to IP addr */
   char c;
   int x, y, z;

   struct sockaddr_in myname;
   int    myname_len;

   if (argc < 3)
    { printf("Usage: %s host port\n", argv[0]);
      exit(1);
    }
   /* ---
      Create a socket
      --- */
   s = socket(AF_INET, SOCK_STREAM, 0);

   /* ---
      Set up Server's Internet address
      - This is the same as in UDP
      --- */
   server.sin_family = AF_INET;			/* Put in the family */
   host_entry_ptr = gethostbyname(argv[1]);     /* Get host info from name */
   if (host_entry_ptr == NULL)
    { printf("Host `%s' not found...\n", argv[1]);
      exit(1);
    }
   memcpy((char *) &(server.sin_addr.s_addr), host_entry_ptr->h_addr,
                host_entry_ptr->h_length);       /* Server's IP addr */

   server.sin_port = htons(atoi(argv[2]));	 /* Server's port number */


   /* ----------------------------------------------
      Here goes......
      ---------------------------------------------- */
   if (connect(s, (struct sockaddr *) &server, sizeof(server) ) < 0)
    { printf("Error: can't connect to %s port %s...\n", argv[1], argv[2]);
      exit(1);
    }


      /* ---------------------------------------
	 Print info of the data socket
	 --------------------------------------- */
   myname_len = sizeof(myname);
   getsockname(s, (struct sockaddr *) &myname, &myname_len);
   printf("The TCP connection is:\n");
   printf("==============================\n");
   printf("My network address is:\n");
   printf("  sin_addr.s_addr = %u\n", myname.sin_addr.s_addr);
   printf("  sin_port        = %u\n\n", myname.sin_port);

      /* -------------------------------------------
	 Print info of peer socket
	 ------------------------------------------- */
   myname_len = sizeof(myname);
   getpeername(s, (struct sockaddr *) &myname, &myname_len);
   printf("The peer socket (server) network address is:\n");
   printf("  sin_addr.s_addr = %u\n", myname.sin_addr.s_addr);
   printf("  sin_port        = %u\n\n", myname.sin_port);

 
   while ( 1 )
   { 
      printf("Enter first number (0 to exit): ");
      scanf("%d", &x);

      if ( x == 0 )
      {
         close(s);
         exit(0);
      }

      printf("Enter second number: ");
      scanf("%d", &y);

      int x1, y1, z1;
      x1 = htonl(x);
      y1 = htonl(y);

      write(s, &x1, 4);
      write(s, &y1, 4);

      read(s, &z1, 4);
      z = htonl(z1);

      printf("%d + %d = %d\n", x, y, z);
   }

   printf("\nDone.\n");
}