erver.sin_port = htons(PORT);   /* Remember htons() from "Conversions" section? =) */

  server.sin_addr.s_addr = INADDR_ANY;  /* INADDR_ANY puts your IP address automatically */  

  bzero(&(server.sin_zero),8); /* zero the rest of the structure */



 

  if(bind(fd,(struct sockaddr*)&server,sizeof(struct sockaddr))==-1){ /* calls bind() */

      printf("bind() error\n");

      exit(-1);

  }    



  if(listen(fd,BACKLOG) == -1){  /* calls listen() */

      printf("listen() error\n");

      exit(-1);

  }



while(1){

  sin_size=sizeof(struct sockaddr_in);

  if ((fd2 = accept(fd,(struct sockaddr *)&client,&sin_size))==-1){ /* calls accept() */

    printf("accept() error\n");

    exit(-1);

  }

 

  printf("You got a connection from %s\n",inet_ntoa(client.sin_addr) ); /* prints client's IP */

 

  send(fd2,"Welcome to my server.\n",22,0); /* send to the client welcome message */

 

  close(fd2); /*  close fd2 */

}

}



/* <---- SOURCE CODE ENDS HERE ----> */







9. A STREAM CLIENT EXAMPLE

=======================================



/* <---- SOURCE CODE STARTS HERE ----> */



#include <stdio.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <netinet/in.h>

#include <netdb.h>        /* netbd.h is needed for struct hostent =) */



#define PORT 3550  /* Open Port on Remote Host */

#define MAXDATASIZE 100   /* Max number of bytes of data */



int main(int argc, char *argv[])

{

  int fd, numbytes;  /* files descriptors */

  char buf[MAXDATASIZE];  /* buf will store received text */

 

  struct hostent *he;         /* structure that will get information about remote host */

  struct sockaddr_in server;  /* server's address information */



  if (argc !=2) {      /* this is used because our program will need one argument (IP) */

    printf("Usage: %s <IP Address>\n",argv[0]);

    exit(-1);

  }



  if ((he=gethostbyname(argv[1]))==NULL){ /* calls gethostbyname() */

    printf("gethostbyname() error\n");

    exit(-1);

  }



  if ((fd=socket(AF_INET, SOCK_STREAM, 0))==-1){  /* calls socket() */

    printf("socket() error\n");

    exit(-1);

  }



  server.sin_family = AF_INET;

  server.sin_port = htons(PORT); /* htons() is needed again */

  server.sin_addr = *((struct in_addr *)he->h_addr);  /*he->h_addr passes "*he"'s info to "h_addr" */

  bzero(&(server.sin_zero),8);



  if(connect(fd, (struct sockaddr *)&server,sizeof(struct sockaddr))==-1){ /* calls connect() */

    printf("connect() error\n");

    exit(-1);

  }



  if ((numbytes=recv(fd,buf,MAXDATASIZE,0)) == -1){  /* calls recv() */

    printf("recv() error\n");

    exit(-1);

  }



      buf[numbytes]='\0';



      printf("Server Message: %s\n",buf); /* it prints server's welcome message =) */



      close(fd);   /* close fd =) */

}



/* <---- SOURCE CODE ENDS HERE ----> */