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

#define S_PORT 7777
#define DATA "Echo-Serving"

main()
{
	int             sd;
	struct sockaddr_in server;
	struct hostent *hp,*gethostbyname();
	char            buf[20],name[20];
	
	int		i; /*zusaetzlich fuer die UDP - Version*/

	/* sd = socket(AF_INET, SOCK_STREAM, 0);   fuer TCP - Verbindung*/ 
	sd = socket(AF_INET, SOCK_DGRAM, 0);	/* fuer UDP - Verbindung*/ 

	gethostname(name,20);
	hp = gethostbyname(name);
	server.sin_family = AF_INET;
	bcopy((char *) hp->h_addr, (char *) &server.sin_addr, hp->h_length);
	server.sin_port = htonl(S_PORT);
	
	/* TCP - Version: 
	
	bind(sd, (struct sockaddr *) & server, sizeof(server));

	connect(sd, (struct sockaddr *) & server, sizeof(server));

	write(sd, DATA, sizeof(DATA));
	read(sd, buf, sizeof(buf));
	
	Ende der TCP - Version */
	
	
	/* UDP - Version:  */
	
	sendto(sd, DATA, sizeof(DATA), 0, (struct sockaddr *)&server,
	sizeof(server));
	
	i = sizeof(server);
	recvfrom(sd, buf, sizeof(buf), 0, (struct sockaddr *)&server, &i);
	
	/* Ende der UDP - Version */
	
	printf("Client bekommt zurueck: %s\n", buf);
	
	close(sd);
}