Hello, new here and need some help please

This is a discussion on Hello, new here and need some help please within the Networking/Device Communication forums, part of the General Programming Boards category; Hi guys, am new here so nice to meet u all i have a problem with a certain client/server program. ...

  1. #1
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    Unhappy Hello, new here and need some help please

    Hi guys, am new here so nice to meet u all
    i have a problem with a certain client/server program.
    the client sends a request to the server and asks it to add 100 to 1557. the server receives the request, does the computation and sends back the results as a string message. can any one help me do this please
    Client code
    Code:
    #include <sys/types.h>
    #include <sys/socket.h>
    #include <netinet/in.h>    	/* defines structure in_addr */
    #include <netdb.h>	   	/* defines structure hostent */
    #include <stdio.h>
    #include <string.h>
    void main( int argc, char **argv)
    {
    
      #define MAXCHAR 80
    
      int size_message, server_len, s; char client_message[MAXCHAR];
    
      struct sockaddr_in   client_addr, server_addr;
    
      struct hostent *server_ptr;
    
    	/* create a connectionless socket with internet domain */
      s = socket(PF_INET,SOCK_DGRAM,0);
    
      	/* fill in data structure of client address */
      client_addr.sin_family = PF_INET;
    
      	/* accept connection on any internet interface */
      client_addr.sin_addr.s_addr = htonl (INADDR_ANY);
    
      	/* assign arbitrary port number */
      client_addr.sin_port= htons(0);
    
      	/* bind local address to the socket */
      bind(s,(struct sockaddr *)&client_addr,sizeof(client_addr)); 
    
    
    
    /* get address of server and fill in its data structure */
      server_ptr = gethostbyname(argv[1]);
      server_addr.sin_family = PF_INET;
      server_addr.sin_addr= *(struct in_addr *)(server_ptr->h_addr); 
      server_addr.sin_port= htons(7785);
      	/* send server a message */
      strcpy (client_message,"ADD 100 to my Id 1557");
      size_message = strlen(client_message);
      printf("The message sent is &#37;s\n", client_message); 
      printf("The server internet address is %s\n",
    				inet_ntoa(*server_ptr->h_addr_list)); 
      sendto(s,client_message,size_message,0,
                  (struct sockaddr *)&server_addr,sizeof(server_addr));
    }
    Server code
    Code:
    #include <sys/types.h>
    #include <sys/socket.h>
    #include <netinet/in.h>    	/* defines structure in_addr */
    #include <netdb.h>	  	/* defines structure hostent */
    #include <stdio.h>
    #include <string.h>
    main()
    {
      #define MAXCHAR 80
      int s;
      struct sockaddr_in    client_addr, server_addr;
      char server_message[MAXCHAR];
      int size_message, client_len;
      	/* create a connectionless socket with internet domain */
      s = socket(PF_INET,SOCK_DGRAM,0);
      	/* fill in data structure of server address */
      server_addr.sin_family = PF_INET;
      server_addr.sin_addr.s_addr = htonl (INADDR_ANY);
      server_addr.sin_port= htons(7785);
      	/* bind local address to the socket */
      bind(s,(struct sockaddr *) &server_addr, sizeof(server_addr)); 
    	while(1) {
    
    /* receive message from client */
      	/* recvfrom blocks until a message arrives */
      	/* it permits to retrieve the source address of message */
      client_len = sizeof (client_addr);
      recvfrom(s,server_message,MAXCHAR,0,
                      (struct sockaddr *)&client_addr,&client_len);
      printf("client address: %s\n", inet_ntoa(client_addr.sin_addr));
      printf("message received from client: %s\n",server_message);
    
    	}
    }

    so pleeeeease can any one help me?? i'll be very grateful

    thanks
    Last edited by Dark1557; 03-30-2008 at 06:20 AM.

  2. #2
    and the hat of int overfl Salem's Avatar
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    So is this a
    - communication problem (the message doesn't arrive)
    - parsing problem (you don't know how to get "100" and "1557" out of the string)
    - a math problem (how to do the addition)

    Or something else?

    Like for example
    - does it compile?
    - using ethereal / wireshark, can you see the message in transit at all?
    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
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    thanks 4 the reply
    the communication is ok
    but the computation is a problem
    i dont know how to do these(
    parsing problem (you don't know how to get "100" and "1557" out of the string)
    - a math problem (how to do the addition)
    )
    also to reply to the client with the results
    i hope u can help me and thank u very much

  4. #4
    and the hat of int overfl Salem's Avatar
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    Perhaps sscanf ?
    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.

  5. #5
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    how can i use it with my program??
    can u explain please
    and thank u very much 4 your time

  6. #6
    CSharpener vart's Avatar
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    Code:
    #include <stdio.h>
    int main(void)
    {
    	int a,b;
    	char buf[] = "ADD 100 to my Id 1557";
    	sscanf(buf,"ADD &#37;d to my Id %d", &a,&b);
    	return 0;
    }
    The first 90% of a project takes 90% of the time,
    the last 10% takes the other 90% of the time.

  7. #7
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    thank u very much

    how should i include it within the program???

  8. #8
    and the hat of int overfl Salem's Avatar
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    Personally, I think you're missing a hell of a lot of basic information on C programming, and you've just launched yourself into the deep end with some network programming.

    Unless you get this in place, then every small step towards whatever you want to do will be a struggle.
    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.

  9. #9
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    actually, am doing this for a friend.
    am not an expert in c programming (sorry!!)

    however, thank you for your help, and vart too.

  10. #10
    and the hat of int overfl Salem's Avatar
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    Perhaps you should ask your friend to join the forum and ask the questions directly.

    You might also consider that if you're doing your friends' homework what exactly you're both getting out of this, because learning by doing is far more effective than just reading about it.
    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.

  11. #11
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    Help?!! Please???

  12. #12
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    If you are trying to become a Formula One mechanic, you probably need to learn how to change the wheels on a regular car first. If you don't understand how to use sscanf() and the code-snippet posted, you probably should be studying the basics first. Network programming is not trivial.

    --
    Mats
    Compilers can produce warnings - make the compiler programmers happy: Use them!
    Please don't PM me for help - and no, I don't do help over instant messengers.

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