can anyone help me?

This is a discussion on can anyone help me? within the Networking/Device Communication forums, part of the General Programming Boards category; I'm trying to write a simple TCP client that is able to connect to a server and send and receive ...

  1. #1
    Registered User
    Join Date
    Dec 2003
    Posts
    2

    can anyone help me?

    I'm trying to write a simple TCP client that is able to connect to a server and send and receive messages and commands.
    The server is suppose to understand these commands:

    AD perform a simple addition
    SB perform a simple subtraction
    DIV perform a simple division
    MUL perform a simple multiplication
    IDENT identify the client and itself
    QUIT break the current connection and wait for a new one

    This is what I got, but there are problems in it. please would anyone have a look and help me out? thank you.

    Code:
    #include<stdio.h>
    #include<String.h>
    #include<sys/types.h>
    #include<sys/socket.h>
    #include<netinet/in.h>
    #include<netdb.h>
    #include<arpa/inet.h>
    
    #define MSGSIZE 64/*size of message buffers*/
    #define PORT 3550/*server port number*/
    
    main(int args,char*argv[]){
    	char sendbuf[MSGSIZE];/*send character buffer*/
    	char recvbuf[MSGSIZE];/*recive character buffer*/
    	Struct sockaddr_in server;/*internet domain server*/
    	int sockket;/*socket descriptor*/
    	int status;/*socket status*/
    	int numbytes;/*number of bytes of message*/
    
    if(argc!=2){
    printf("Usage:%s<IP Address>\n",argv[0]);
    exit(-1);
    }
    
    
    
    
    /*Server details */
    server.sin_family=AF_INET;
    Server.sin_addr.s_addr=inet_addr(argv[1]);
    servsr.sin_port=htons(PORT);
    
    Printf("valid IP address,connecting to....%s\n",argv[1]);
    
    /*connet to server*/
    if (status=connect(socket,(struct sockaddr*)&server,sizeof (server))<0){
    close(socket);
    perror("connect");
    exit(1);
    }
    
    /*recieve message from server*/
    
    if (numbytes=recv(socket,recvbuf,sizeof(recvbuf),0)<0){
    perror("recv");
    exit(1);
    }
    
    /*print response from server*/
    recvbuf[numbytes]='\0';
    printf("%s\n\n",recvbuf);
    
    /*Being main loop */
    for(; ;){
    printf("Input a command(AD,SB,DIV,MUL,IDENT,QUIT)\n");
    
    /*get command from user*/
     get(sendbuf);
    /*send command to server*/
    status=send(sock,sendbuf,sizeof(sendbuf),0);
    if (status<0){
    perror("send");
    exit(1);
    }
    
    /*recieve message from server*/
    numbytes=recv(socket,recvbuf,sizeof(recvbuf),0);
    if(states<0){
    perror("send");
    exit(1);
    }
    
    /*Print response frpm server*/
    recvbuf[numbytes]='\0';
    printf("%s\n\n",recvbuf);
    
    if[strncmp(sendbuf,"QUIT",4)==0){
    break;
    }
    
    }
    
    
    close(socket);
    printf("connection closed....\n");
    
    return 0;
    }
    Attached Files Attached Files

  2. #2
    and the hat of int overfl Salem's Avatar
    Join Date
    Aug 2001
    Location
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    Posts
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    I dunno which is your bigger problem - whether it's how to use sockets, or simple problems of broken 'C' syntax

    > Printf("valid IP address,connecting to....%s\n",argv[1]);
    C is case sensitive Printf != printf

    > if[strncmp(sendbuf,"QUIT",4)==0)
    What's with the square bracket?

    I suggest you first get the read a command loop sorted out before you try and send/recv it to another process
    Code:
    while ( fgets( buff, sizeof buff, stdin ) != NULL ) {
        if ( strncmp( buff, "QUIT", 4 ) == 0 ) break;
        printf( "%s", buff );
    }
    When you've done that, read
    Useful Links And Good Books
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  3. #3
    Registered User
    Join Date
    Nov 2001
    Posts
    1,348
    I highly recommend Network Programming for Microsoft Windows, Second Edition by Anthony Jones and Jim Ohmund.

    Check out this FAQ.

    http://www.tangentsoft.net/wskfaq/

    Kuphryn

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