Thread: Client/Server Switch using Buffer

Hello and Happy Thanksgiving. I am working on a simple TCP Client Server poker game, and have run into a little problem. I am not the best programmer. I am modifying a previously used TCP Echo program for this.

I want the client to simply do display work, while the server handles everything else. In the client, I display a menu, and then read the input into buffer, and send to server. What I then want to do is take the input that is sent to server, and run it through a switch statement to send it to the play function, or the stats function, or quit. I am unsure of how to do a switch statement, or anything of the sort using the buffer however. I know how to use switch statements of course, just not with a buffer that is sent from another program. Any help is appreciated.

Client:

Code:

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

void error(char *msg)
{
    perror(msg);
    exit(0);
}

int main(int argc, char *argv[])
{
    int sockfd, portno, n;
	int choice;
    struct sockaddr_in serv_addr;
    struct hostent *server;

    char buffer[256];
    if (argc < 3) {
       fprintf(stderr,"usage %s hostname port\n", argv[0]);
       exit(0);
    }
    portno = atoi(argv[2]);
    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd < 0) 
        error("ERROR opening socket");
    server = gethostbyname(argv[1]);
    if (server == NULL) {
        fprintf(stderr,"ERROR, no such host\n");
        exit(0);
    }
    bzero((char *) &serv_addr, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    bcopy((char *)server->h_addr, 
         (char *)&serv_addr.sin_addr.s_addr,
         server->h_length);
    serv_addr.sin_port = htons(portno);
    if (connect(sockfd,(struct sockaddr *)&serv_addr,sizeof(serv_addr)) < 0) 
        error("ERROR connecting");
		
	printf(" \n");
	printf("*****************************************\n");
	printf("Welcome to the World Famous Davis' Poker!\n");
	printf("*****************************************\n");
	printf(" \n");
		
	while (buffer != NULL)
	{
	
		printf("Please select an action:\n");
		printf("1 - Play Poker\n");
		printf("2 - View Statistics\n");
		printf("3 - Quit\n");
		printf("\n");
		printf("Selection: ");
		
    bzero(buffer,256);
    fgets(buffer,255,stdin);
    n = write(sockfd,buffer,strlen(buffer));
    if (n < 0) 
         error("ERROR writing to socket");
    bzero(buffer,256);
    n = read(sockfd,buffer,255);
    if (n < 0) 
         error("ERROR reading from socket");
    printf("%s\n",buffer);
	}
    return 0;
}

Server:

Code:

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

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

int main(int argc, char *argv[])
{
     int sockfd, newsockfd, portno, clilen;
     char buffer[256];
	 char c;
	 int choice;
     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 = 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);
     newsockfd = accept(sockfd, 
                 (struct sockaddr *) &cli_addr, 
                 &clilen);
     if (newsockfd < 0) 
          error("ERROR on accept");
		  
	while (buffer != NULL) {
     bzero(buffer,256);
     n = read(newsockfd,buffer,255);
     if (n < 0) error("ERROR reading from socket");
	
     printf("Here is the message: %s\n",buffer);
     n = write(newsockfd,"I got your message",18);
     if (n < 0) error("ERROR writing to socket");
	 }
     return 0; 
}

You could also use an enum.

Code:

#include <stdio.h>

enum {play=1,stats,quit};
int main (void){
    int input;
    scanf (" %d",&input);
    switch (input){
        case play:
        printf ("Play!\n");
        break;
        case stats:
        printf ("Stats!\n");
        break;
        default:
        printf ("Quitting...%i\n", input);
    } return 0;
}

generated with Anchor | freshmeat.net

Since I am only inputting an integer anyway, be it '1' for play poker, '2' for view stats, etc, would there be an easier way to do this? Instead of reading in to a buffer, could I just scanf into a variable, say 'choice' and then send that variable, 'choice' in the

Code:

n = write(sockfd,buffer,strlen(buffer));

call in place of buffer?

Whatever I do, I just have to be able to send the input through write to the client, and do the switch and function calls there.

the second arg of the write functin is "const void *", you can read the num into an integer and pass the address of the integer to the second arg：

Code:

scanf("%d",&num);
switch(num)
{
   case 1：
    printf ("Play!\n");
      break;
}
write(sockfd,&num,1);

try it ..