Hi Class,

   This is NOT an assignment.  Some of you are less familiar with the
Unix (Solaris) system and the C programming language.  We cannot teach you
the details of Unix and C, but we can help you refresh and get started
with them.  If you like, you can try to write a simple C program as 
described in the following.  Our TAs will be happy to answer any questions
you have regarding Unix and C.  We will also set aside a couple of
discussion sessions to help you on C programming.  The book on C by
Kernighan and Ritchie (or any C programming language book) will be a good
place to start.  Online man pages are also helpful.  This exercise is optional.
You don't have to turn in anything.    


OBJECTIVE:

To attain familiarity with pointers, structures, command line parameters, 
string tokens, file input and output, and miscellaneous data types and    
control statements in the C language.


PROBLEM STATEMENT:

Write a program that creates a linked list of structures by reading data  
from a file in the current directory specified by the first command line  
parameter.  Then sort the list in place, without creating any additional
nodes or structure variables.  Finally, display the contents of the linked
list by traversing the list, in order, and writing the results to the file
specified by the second command line parameter in the same format as the  
input file.


DETAILS:

  (1)  The structure contains the following items:
            a character array of size 20,
            an integer

  (2)  The input file contains a random number of lines, each having the
       following format:  a character string (consisting of only letters,
       digits, and underscores), a comma, and an integer.  There will
       be no spaces on either side of the comma.  For example:

            oicu812,23
            theyregr8,90210

       Note: the character string may contain between one and twenty
       characters, and each may be a different length (as illustrated
       in the example).

  (3)  The input file will exist and will be in the appropriate format.

  (4)  The output file should be in the same format as the input, with
       the lines sorted BY THE INTEGER FIELD.


SAMPLES:

  You must create test input files for your program.  Below are some
  sample input files and the resulting output files.

  SAMPLE 1:

      input file                       output file
      -----------------------          -----------------------
      abcdefg,12345                    me,1
      eio298ajfke,2383                 owejkc923,203
      owejkc923,203                    eio298ajfke,2383
      youck239,992381                  wrjwrlk,3929
      me,1                             abcdefg,12345
      wrjwrlk,3929                     youck239,992381


  SAMPLE 2:

      input file                       output file
      -----------------------          -----------------------
      four,4444                        one,1
      three,333                        two,22
      two,22                           three,333
      six,666666                       four,4444
      five,55555                       five,55555
      one,1                            six,666666