1- I try \r\n before, it didn't work(no answer from server)
that is why I use \n\n.
2-3- I also try before combination with and without
Keep-Alive & Host. But still doesn't work for www.altavista.com
Maybe you didn't see the combination that I tried because of
the bad indentation. Here is the code again with indentation
and without error handling case so it is easier to read.
Execution line: ./testing www.yahoo.com

#include <stdio.h>
#include <netdb.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h> // htons(), htonl()
#include <string.h>
#include <iostream.h>

int main(int argc, char *argv[])
{
   // Socket connection
   struct sockaddr_in sin;
   sin.sin_family	= AF_INET;
   sin.sin_port	= htons(80);
	
   struct hostent *host;
   host = gethostbyname(argv[1]);
	
   if(host == NULL)	// Unresolve host name.
   {
      fprintf(stderr, "gethostbename() failed");
      exit(1);
   }
   else
   {
      // Copy host address to sock.
      memcpy((caddr_t)& sin.sin_addr, host->h_addr,        
                
              host->h_length);
   }

   // IPPROTO_TCP == 0.
   int sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	
if(connect(sock, (struct sockaddr *) &sin, sizeof(sin)) < 0)
   {
      perror("connect() failed!");
      close(sock);
      exit(1);		
   }
	
   char szbuffer[1445];
	
   // Prepare the request string.
   strcpy(szbuffer, "GET / HTTP/1.1\nHost: www.yahoo.com\n\n ");

   // Send request.
   if(send(sock, szbuffer, strlen(szbuffer), MSG_OOB) < 0)
   {
      perror("send() failed!");
      exit(1);
   }

   // Clear szbuffer.
   memset(szbuffer, '\0', sizeof(szbuffer));

   // Open file to be written on.
   FILE *stream;
   if((stream = fopen("t.htm", "wb")) == NULL)
      perror("Can not write file!");
	
   int numBytesRecv=0, i=0;

while( (i = recv(sock, szbuffer, sizeof(szbuffer), 0)) > 0 )
{
  numBytesRecv += fwrite(szbuffer, sizeof(char), i, stream);
  memset(szbuffer, '\0', sizeof(szbuffer));
}

   printf("Number of Bytes received: %i\n", numBytesRecv);

   return 0;
}