server.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h> 
#include <sys/socket.h>
#include <netinet/in.h>
int newsockfd;
int sockfd;
char matrix[3][3];  /* the tic tac toe matrix */
int counter=0;
char check(void);
void init_matrix(void);
void get_player_move(void);
void get_client_move(void);
void disp_matrix(void);

void error(const char *msg)
{
    perror(msg);
    exit(1);
}

int main(int argc, char *argv[])
{
     int portno;
     socklen_t clilen;
    
     struct sockaddr_in serv_addr, cli_addr;
     int n;
     
     if (argc < 2) {
         fprintf(stderr,"ERROR, no port provided\n");
         exit(1);
     }
     
     sockfd = socket(AF_INET, SOCK_STREAM, 0);
     if (sockfd < 0) 
        error("ERROR opening socket");
     
        
     bzero((char *) &serv_addr, sizeof(serv_addr));
     
     
     portno = atoi(argv[1]);
     
     serv_addr.sin_family = AF_INET;
     serv_addr.sin_addr.s_addr =inet_addr("127.0.0.1"); //INADDR_ANY;
     serv_addr.sin_port = htons(portno);
     
     if (bind(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0) 
             error("ERROR on binding");
             
     listen(sockfd,5);
     clilen = sizeof(cli_addr);

     puts("This is the game of Tic Tac Toe.\n");
     puts("waiting connection to established....\n");

     
      newsockfd = accept(sockfd, (struct sockaddr *) &cli_addr, &clilen);
      if (newsockfd < 0) 
          error("ERROR on accept");
    
     
    char done;

  
  done =  ' ';
  init_matrix();
  
  
  do {
  	
	    disp_matrix();
	    puts("waiting for client move\n");
	     get_client_move();
	    
	    disp_matrix();
	    done = check(); /* see if winner */
	    if(done!= ' ') break; /* winner!*/
	    get_player_move();
	  
	    disp_matrix();
	    done = check(); /* see if winner */
  } while(done== ' ');

	  if(done=='X') printf("Player X won!\n");
	  else printf("Player O won!!!!\n");
	  disp_matrix(); /* show final positions */
     
        
     close(newsockfd);
     close(sockfd);
     return 0; 
}


void init_matrix(void)
{
	  int i, j;

	  for(i=0; i<3; i++)
	    for(j=0; j<3; j++) matrix[i][j] =  ' ';
}


void get_player_move(void)
{
  
    int x, y,i,j,n;

  	printf("Enter X,Y coordinates for Player O: ");
  	scanf("%d%*c%d", &x, &y);
  	int temp1=htonl(x);
  	int temp2=htonl(y);

	  n=write(newsockfd,&temp1,sizeof(temp1));
	  if(n<0)
	    error("write failed");
	  n=write(newsockfd,&temp2,sizeof(temp2));
	  if(n<0)
	    error("write failed");
	  if(n=0)
		error("client closed");

	  x--; y--;

	  if(matrix[x][y]!= ' '){
	  	  	printf("Invalid move, try again.\n");
 	    	get_player_move();
       }
  	  else matrix[x][y] = 'O';
  	  
    counter++;
  
}

/* Display the matrix on the screen. */
void disp_matrix(void)
{
  int t;

  for(t=0; t<3; t++) {
    printf(" %c | %c | %c ",matrix[t][0],
            matrix[t][1], matrix [t][2]);
    if(t!=2) printf("\n---|---|---\n");
  }
  printf("\n");
}

/* See if there is a winner. */
char check(void)
{
  int i,j;

  for(i=0; i<3; i++)  /* check rows */
    if(matrix[i][0]==matrix[i][1] &&
       matrix[i][0]==matrix[i][2]) return matrix[i][0];

  for(i=0; i<3; i++)  /* check columns */
    if(matrix[0][i]==matrix[1][i] &&
       matrix[0][i]==matrix[2][i]) return matrix[0][i];

  /* test diagonals */
  if(matrix[0][0]==matrix[1][1] &&
     matrix[1][1]==matrix[2][2])
       return matrix[0][0];

  if(matrix[0][2]==matrix[1][1] && matrix[1][1]==matrix[2][0])
       return matrix[0][2];
       
   if(counter==9)
   {
   printf("draw\n");
   exit(0);
   }
      
  return ' ';
}
void get_client_move(void)
{
  	int x, y,i,j;

 
	int n;
	n=read(newsockfd,&i,sizeof(i));
	n=read(newsockfd,&j,sizeof(j));
	if(n<0)
	error("error on reading");
	if(n=0)
		error("client closed");
	x=ntohl(i);
	y=ntohl(j);


	  x--; y--;

	  if(matrix[x][y]!= ' '){
	    printf("Invalid move, try again.\n");
	    get_client_move();
	  }
	  else matrix[x][y] = 'X';
	   counter++;
  
}