[gameprogrammer] networked tic tac toe server
- From: Chris Nystrom <cnystrom@xxxxxxxxx>
- To: gameprogrammer@xxxxxxxxxxxxx
- Date: Fri, 21 May 2010 21:37:26 -0500
I wrote this to test some networking routines. Experienced programmers
may want to critique. Comments welcome. Beginning programmers might
find something useful.
Thanks,
Chris
--
/* tic_tac_toe.c
*
* (c) 2010 Chris Nystrom
*
* Public Domain
*
* Use this for whatever you want
*
* compiles with no errors on linux
*
* Start this server then telnet to the server using port 32662
("telnet localhost 32662") to play. You must have 2 players.
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#ifndef FALSE
#define FALSE (0)
#endif
#ifndef TRUE
#define TRUE !FALSE
#endif
/* the port users will be connecting to */
#define MYPORT 32662
/* how many pending connections queue will hold */
#define BACKLOG 10
/* listener socket */
int sockfd;
void init_server(void)
{
/* my address information */
struct sockaddr_in my_addr;
int yes = 1;
if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
perror("socket() error");
exit(1);
} else
printf("socket() sockfd (listener) is: %d\n", sockfd);
if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int))
== -1) {
perror("setsockopt() error");
exit(1);
} else
printf("setsockopt() is OK...\n");
/* host byte order */
my_addr.sin_family = AF_INET;
/* short, network byte order */
my_addr.sin_port = htons(MYPORT);
/* automatically fill with my IP */
my_addr.sin_addr.s_addr = INADDR_ANY;
printf("Using %s and port %d...\n", inet_ntoa(my_addr.sin_addr),
MYPORT);
/* zero the rest of the struct */
memset(&(my_addr.sin_zero), '\0', 8);
if (bind
(sockfd, (struct sockaddr *) &my_addr,
sizeof(struct sockaddr)) == -1) {
perror("bind() error");
exit(1);
} else
printf("bind() is OK...\n");
if (listen(sockfd, BACKLOG) == -1) {
perror("listen() error");
exit(1);
}
printf("listen() is OK...\n");
printf("Listening...\n");
}
int new_connection(void)
{
int new_fd;
socklen_t sin_size;
/* connector’s address information */
struct sockaddr_in their_addr;
sin_size = sizeof(struct sockaddr_in);
if ((new_fd =
accept(sockfd, (struct sockaddr *) &their_addr,
&sin_size)) == -1) {
perror("accept() error");
exit(1);
} else
printf("accept() is OK...\n");
printf("socket %d: Connection from %s\n", new_fd,
inet_ntoa(their_addr.sin_addr));
return (new_fd);
}
void write_to_socket(int fd, char *s)
{
if (send(fd, s, strlen(s), 0) == -1)
perror("send() error");
// else
// printf ("send is OK...!\n");
}
#define BUF_SIZE (1024)
void printf_to_socket(int fd, const char *format, ...)
{
char s[BUF_SIZE];
va_list ap;
va_start(ap, format);
vsnprintf(s, BUF_SIZE, format, ap);
va_end(ap);
write_to_socket(fd, s);
}
int read_from_socket(int fd, char *buf)
{
int nbytes;
if ((nbytes = recv(fd, buf, sizeof(buf), 0)) <= 0) {
if (nbytes == 0)
/* connection closed */
printf("socket %d hung up\n", fd);
else
perror("recv() error");
}
return (nbytes);
}
void close_socket(int fd)
{
close(fd);
printf("socket %d: closed...\n", fd);
}
#define NUM_OF_PLAYERS (2)
int fd[NUM_OF_PLAYERS];
int num_players = NUM_OF_PLAYERS;
void read_from_player(int player, char *s)
{
read_from_socket(fd[player - 1], s);
}
void write_to_player(int player, char *s)
{
write_to_socket(fd[player - 1], s);
}
void write_to_other_player(int player, char *s)
{
/* switch player */
if (1 == player) {
player = 2;
} else {
player = 1;
}
write_to_player(player, s);
}
void write_to_all_players(char *s)
{
int i;
for (i = 0; i < num_players; i++) {
write_to_socket(fd[i], s);
}
}
void printf_to_player(int player, const char *format, ...)
{
char s[BUF_SIZE];
va_list ap;
va_start(ap, format);
vsnprintf(s, BUF_SIZE, format, ap);
va_end(ap);
write_to_player(player, s);
}
void printf_to_other_player(int player, const char *format, ...)
{
char s[BUF_SIZE];
va_list ap;
va_start(ap, format);
vsnprintf(s, BUF_SIZE, format, ap);
va_end(ap);
write_to_other_player(player, s);
}
void printf_to_all_players(const char *format, ...)
{
char s[BUF_SIZE];
va_list ap;
va_start(ap, format);
vsnprintf(s, BUF_SIZE, format, ap);
va_end(ap);
write_to_all_players(s);
}
void init_game(void)
{
char sTitle[] = "\nTic Tac Toe Server v1.0\n\n";
init_server();
fd[0] = new_connection();
printf("Player 1 has joined.\n");
fd[1] = new_connection();
printf("Player 2 has joined.\n");
write_to_all_players(sTitle);
}
void print_guide(void)
{
write_to_all_players("Select moves from this grid:\n\n");
write_to_all_players(" 1 | 2 | 3\n");
write_to_all_players("----------\n");
write_to_all_players(" 4 | 5 | 6\n");
write_to_all_players("----------\n");
write_to_all_players(" 7 | 8 | 9\n");
}
int board[9] = { 0 };
void reset_game(void)
{
int i;
for (i = 0; i < 9; i++) {
board[i] = 0;
}
}
void print_board(void)
{
int i;
int count = 0;
write_to_all_players("\n");
for (i = 0; i < 9; i++) {
if (1 == board[i]) {
write_to_all_players(" X ");
} else if (2 == board[i]) {
write_to_all_players(" O ");
} else {
write_to_all_players(" . ");
}
count++;
if (3 == count) {
write_to_all_players("\n");
if (i < 8) {
write_to_all_players("-----------\n");
}
count = 0;
} else {
write_to_all_players("|");
}
}
write_to_all_players("\n");
}
int get_move(int player)
{
int move = 0;
char buf[1024];
printf_to_other_player(player, "Waiting on player %d...\n", player);
while (move < 1 || move > 9) {
printf_to_player(player, "Player %d move: ", player);
read_from_player(player, buf);
move = atoi(buf);
if (board[move - 1] != 0) {
write_to_player(player, "That spot already taken!\n");
move = 0;
}
}
printf_to_other_player(player, "Player %d move: %d\n", player, move);
return (move);
}
void process_move(int player, int move)
{
board[move - 1] = player;
}
int check_for_winner(void)
{
int winner = FALSE;
/* across */
if ((board[0] != 0) && (board[0] == board[1])
&& (board[1] == board[2])) {
winner = board[0];
}
if ((board[3] != 0) && (board[3] == board[4])
&& (board[4] == board[5])) {
winner = board[3];
}
if ((board[6] != 0) && (board[6] == board[7])
&& (board[7] == board[8])) {
winner = board[6];
}
/* down */
if ((board[0] != 0) && (board[0] == board[3])
&& (board[3] == board[6])) {
winner = board[0];
}
if ((board[1] != 0) && (board[1] == board[4])
&& (board[4] == board[7])) {
winner = board[1];
}
if ((board[2] != 0) && (board[2] == board[5])
&& (board[5] == board[8])) {
winner = board[2];
}
/* diagonal */
if ((board[0] != 0) && (board[0] == board[4])
&& (board[4] == board[8])) {
winner = board[4];
}
if ((board[2] != 0) && (board[2] == board[4])
&& (board[4] == board[6])) {
winner = board[4];
}
return (winner);
}
void close_all_sockets(void)
{
int i;
for (i = 0; i < num_players; i++) {
close_socket(fd[i]);
}
}
void play_game(void)
{
int player = 1;
int winner = FALSE;
int draw = FALSE;
int move;
int count = 0;
reset_game();
print_guide();
print_board();
while (!winner && !draw) {
move = get_move(player);
printf_to_other_player(player, "%d\n", move);
process_move(player, move);
print_board();
winner = check_for_winner();
count++;
if (!winner && 9 == count) {
draw = TRUE;
}
/* switch player */
if (1 == player) {
player = 2;
} else {
player = 1;
}
}
write_to_all_players("\nGame over!\n\n");
if (winner) {
printf_to_all_players("The winner is player %d!\n\n", winner);
}
if (draw) {
write_to_all_players("The game was a draw! No winner!\n\n");
}
}
int main(int argc, char *argv[])
{
init_game();
play_game();
close_all_sockets();
exit(0);
}
--
E-Mail: Chris Nystrom <cnystrom@xxxxxxxxx>
Saving the world from web programming.
http://www.newio.org - G-Talk: cnystrom
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