Jeg kom acors denne kodning når surfin de net.this kode værker perfectly.but som jeg er ny til denne socket programmering jeg brug sm coments noteret på det eller forklaring på denne kildekode.
Jeg har PRB forståelse af server.ci har indsendt den nedenfor
kan u fyrene hjælpe mig!
cheerZ


Den server.c

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <sys/time.h>
#define MAX_CLIENTS 64

struct sockaddr_in servaddr;
int addr_len;
struct sockaddr addr;
struct sockaddr_in *ptr;
int cl_addr_len;
struct sockaddr_in cl_addr;
char in_buf[100], out_buf[100];
char names [10][30];
char message[150];
int num_names = 0;

	typedef struct cl_info
		{
			char cl_id[30];
			int cl_status;
		}cl_info;

	cl_info clients[MAX_CLIENTS];

	int main(int argc, char **argv)
		{
			int newsockfd;
			int sockfd;
			int nbytes;
			int max_fd;
			int fd;
			short func_num;

			fd_set test_set, ready_set;



	sockfd = socket(AF_INET, SOCK_STREAM, 0); 
	servaddr.sin_family - AF_INET;
	servaddr.sin_port = 0;				 /*choose an unused port at random */
	servaddr.sin_addr.s_addr = INADDR_ANY;	 	/* auto fill with my IP address */
	bind(sockfd,(struct sockaddr*) &servaddr, sizeof(servaddr));

	addr_len = sizeof(addr);
	getsockname(sockfd, &addr, &addr_len);
	ptr = (struct sockaddr_in *)&addr;
	printf("\nServer on port# %d\n", ptr->sin_port);

	listen(sockfd, 5);
	max_fd = sockfd; 
	FD_ZERO(&test_set); /*clear the listening socket */

	FD_SET(sockfd, &test_set);

	

	while(1)
		{
			memcpy(&ready_set, &test_set, sizeof(test_set));
			select(max_fd+1, &ready_set, NULL, NULL, NULL);
			
			if(FD_ISSET(sockfd, &ready_set)) /*if listening sock has data its a call from new client */
				{
					/*create a new socket */

					cl_addr_len = sizeof(cl_addr);
					newsockfd = accept(sockfd, (struct sockaddr *)&cl_addr, &cl_addr_len);

					printf("\nA new connection has been made to socket %d\n", newsockfd);
					FD_SET(newsockfd, &test_set); /* add new socket to list */
					if(newsockfd > max_fd)
						max_fd = newsockfd; /*update max_fd with new socket file discriptor */
				} /*end if*/


			for(fd=0; fd <= max_fd; fd++) /*loop through connected socket file discriptors */
{
if((fd !=sockfd) && FD_ISSET(fd, &ready_set))/*bypass listening sock if sock has data*/
if(process_call(fd, max_fd) == 0) /*if socket is closed */
{
printf("\nThe listening socket is now closed\n");
close(newsockfd);
printf("\nClient on socket %d has left the room\n", sockfd);
FD_CLR(fd, &test_set); /*remove socket from list */
/*decrement user count */
} /*end if */
} /* end for loop */
} /*end while loop */
return 0;
} /*end main */
int add_name(int sockfd)
{
int nbytes;
short name_len;
short n_name_len;

printf("\nAdding name .....\n");
nbytes = read(sockfd, (char *)&name_len, sizeof(short));
name_len = ntohs(name_len); /*convert name_len from network to host short */
memset(clients[sockfd].cl_id, 0, 30); /*set all bytes to zero */
nbytes = read(sockfd, clients[sockfd].cl_id, name_len);
num_names ++; /*increment user count */
printf("\n%s has joined the chat room\n", clients[sockfd].cl_id);

/*need to broadcast user has joined plus user id to connected clients here */

} /*end add_name function */
int how_many(int sockfd, int max)
{
int sock;
short user_len;
char username[30];

for(sock = 4; sock <= max; sock++)
{
strcpy(username, clients[sock].cl_id);

user_len = htons(strlen(username));
write(sockfd, (char *)&user_len, sizeof(short));
write(sockfd, username, strlen(username));
send_user_list(sockfd, username);
}
} /*end how_many function */
int send_user_list(int sockfd, char *users)
{
short msg_type;
short user_len;

msg_type = htons(2);
printf("msg_type is : %u\n", msg_type);
write(sockfd, &msg_type, sizeof(short));

user_len = htons(strlen(users));
write(sockfd, (char *)&user_len, sizeof(short));
write(sockfd, users, strlen(users));
}
int find_name(int sockfd, int max)
{
char search_name[30];
int sock;
int found = 0;
short len, name_len;
char sender[30];
short sender_len;
char msg[150];
short msg_len;

memset(search_name, 0, 30); /*set all bytes to zero */
printf("\nReceiving userid......\n");
read(sockfd, (char *)&name_len, sizeof(short));
len = ntohs(name_len);
read(sockfd, search_name, len);
read(sockfd, &msg_len, sizeof(short));
msg_len = ntohs(msg_len);
read(sockfd, msg, msg_len);
msg[msg_len] = '\0';

strcpy(sender, clients[sockfd].cl_id);

for(sock = 4; sock <= max; sock++)
{
printf(" %d is held in max\n", max);
printf("\ncomparing search request for %s with %s username\n",
search_name, clients[sock].cl_id);
if(strcmp(search_name, clients[sock].cl_id) ==0)
{
printf("\nuserid found\n");
found = 1;
send_async_msg(sock, msg,sender);
}/*end if */
} /*end for loop */

if(! found)
{
printf("\nuserid not found\n");
} /*end if */
}/*end find_name function */
int process_call(int newsockfd, int max_fd)
{
int nbytes;
short func_num;

nbytes = read(newsockfd, (char *)&func_num, sizeof(short));
if(nbytes ==0)
return 0;
if (nbytes != sizeof(short))
{
perror("\nUnknown menu option!\n");
exit(1);
} /* end if */

func_num = ntohs(func_num);
switch(func_num)
{
case(1):
add_name(newsockfd);
break;
case(2):
how_many(newsockfd, max_fd);
break;
case(3):
find_name(newsockfd, max_fd);
break;
case(4):
send_global_msg(newsockfd, max_fd);
break;
case(5):
printf("\nShutting down Server...\n");
exit(0);
default:
printf("\nUnknown function number!\n");
break;
} /*end switch */
} /*end process_call function */
int send_async_msg(int sockfd, char * msg, char *sender)
{
short msg_type;
short msg_len;
short sender_len;

msg_type = htons(1);
printf("msg_type is : %u\n", msg_type);
write(sockfd, &msg_type, sizeof(short));
msg_len = htons(strlen(msg));
write(sockfd, (char *)&msg_len, sizeof(short));
write(sockfd, msg, strlen(msg));

sender_len = htons(strlen(sender));
write(sockfd, (char *)&sender_len, sizeof(short));
write(sockfd, sender, strlen(sender));
}/* end of send_async_msg function */
int send_global_msg(int sockfd, int max_fd)
{
int nbytes;
int sock;
short len;
short msg_type;
char msg[150];
char sender[30];
short sender_len;

strcpy(sender, clients[sockfd].cl_id);

msg_type = 1;
memset(in_buf, 0, sizeof(in_buf)); /*set all to zero */
nbytes = read(sockfd, &len, sizeof(short));
len = ntohs(len);
read(sockfd, msg, len);
message[len] = '\0';
for(sock = 4; sock <= max_fd; sock++)
{
send_async_msg(sock, msg, sender);
} /*end for loop */
} /* end of send_global_msg function */