The *.c files contain an example that shows how to establish a 
 datagram based communication in Internet domain. The programs 
 are contained in example ex2a.c and  ex2b.c. Before you execute
 the two programs, you need to compile them at the machine where
 you plan to execute them. Let us assume that these machines
 are local and remote. At local, issue the command:

 cc -o  ex2a ex2a.c  OR
 gcc -o ex2a ex2a.c -lsocket

 This will produce an executable code, ex2a.
 
 At remote, issue the commande: 
  cc -o  ex2b ex2b.c OR
  gcc -o ex2b ex2b.c -lsocket -lnsl

 This will produce an executable code, ex2b.

 To execute the program :                                               
    At the local machine type ex2a and get the port number.             
    At the remote machine type ex2b with host address and              
    port number.                                                       
                                                                       
 local> ex2a                                                           
       socket has port 1664                                                 
                             remote> ex2b local.cis.pitt.edu 1664          
                                          -----

  where local is the name of the local machine where you executed
        -----
  ex2a. I am assuming that machine resides in the cis domain. Otherwise
  the name of the machine has to been changed (i.e, zeus.cs.pitt.edu, for
  example if I am running these programs in the cs domain.)
                                                                       
  To test time out, execute ex2a at the local site without executing   
  ex2b at the remote site. ex2a should timeout after TIMER. You 
  can change the values of TIMER for a shorter or longer timeouts.