CODEWITHSUNDEEP
csocketsudp
user2825479
user2825479

Reputation: 1

socket programming unable to extract data sent from client in c

my program is a simple UDP client-server program, in this the data sent by the client is stored in variable mesg(in the server), So basically I am trying to extract the first character of the data element(using mesg[0]) and print it on the terminal. but this doesnt happen:( here is the code for the server and client.

server /* Sample UDP server */

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

int main(int argc, char**argv)
{
   int sockfd,n=0;
   struct sockaddr_in servaddr,cliaddr;
   socklen_t len;
   char mesg[1000];

   sockfd=socket(AF_INET,SOCK_DGRAM,0);

   bzero(&servaddr,sizeof(servaddr));
   servaddr.sin_family = AF_INET;
   servaddr.sin_addr.s_addr=htonl(INADDR_ANY);
   servaddr.sin_port=htons(32000);
   bind(sockfd,(struct sockaddr *)&servaddr,sizeof(servaddr));

   for (;;)
   {
      len = sizeof(cliaddr);
      n = recvfrom(sockfd,mesg,1000,0,(struct sockaddr *)&cliaddr,&len);
      sendto(sockfd,mesg,n,0,(struct sockaddr *)&cliaddr,sizeof(cliaddr));
      printf("-------------------------------------------------------\n");
      mesg[n] = 0;
      printf("Received the following:\n");

printf("%s \n", mesg[0]);

   }
}

client

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

int main(int argc, char**argv)
{
   int sockfd,n;
   struct sockaddr_in servaddr,cliaddr;
   char sendline[1000];
   char recvline[1000];

   if (argc != 2)
   {
      printf("usage:  udpcli <IP address>\n");
      exit(1);
   }

   sockfd=socket(AF_INET,SOCK_DGRAM,0);

   bzero(&servaddr,sizeof(servaddr));
   servaddr.sin_family = AF_INET;
   servaddr.sin_addr.s_addr=inet_addr(argv[1]);
   servaddr.sin_port=htons(32000);

   while (fgets(sendline, 10000,stdin) != NULL)
   {
      sendto(sockfd,sendline,strlen(sendline),0,
             (struct sockaddr *)&servaddr,sizeof(servaddr));
      n=recvfrom(sockfd,recvline,10000,0,NULL,NULL);
      recvline[n]=0;
      fputs(recvline,stdout);
   }
}
}

Upvotes: 0

Views: 373

Answers (1)

Duck
Duck

Reputation: 27542

The only thing I see is this

printf("%s \n", mesg[0]);

which should be

printf("%s \n", mesg);

or

printf("%c \n", mesg[0]);

if you are really intent on printing a single character.

Otherwise it seems to work.

Upvotes: 2

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