COMP 340, Fall 2014
Instructor: Dan Harris
Assignment #2
Date: March 17, 2016
Due on March 2, 2016.

* late assignment will be graded-down progressively by
  10% for each day late.

  
Q1. Write a C program Gen.c that generates a ordered sequence 
    of 20 random numbers within a range of 1000 to 9999. The 
    program is invoked by a command line 
       % gen datfile1
    In the above line, gen is the executable, datfile1 is the
    argument to the execution of gen. It specifies the name of 
    the output file for the 20 random numbers.

    To make Gen.c possible, your main() program should accept
    arguments like
       #include <stdio.h>
       void main (int argc, char *argv[])
       {
          char *fname = argv[1];          
          ....
          fp = fopen(fname,"w");
          ....

Q2. Write a C program Sort.c that performs a merge sort on 2 
    number sequences produced by the program in Q1. Sort.c
    should spawn 2 processes and each of the children processes
    would exec() the Gen program to produce a sequence.
    Sort.c should also specify the filenames for the number
    sequences when spawning the children processes. The parent
    process should then wait for the termination of the children
    processes and perform a merge sort on the 2 data files. The
    final sorted sequence is written to the file "Sort.out".

    The algorithm for merge sort could be roughly described as
    1. read num1 from datafile1
    2. read num2 from datafile2
    3. write the smaller between num1 and num2 to output
    4. "refill" num1 or num2 according to which one has been
       outputted in step(3).
    5. repeat (3) and (4) until both files are exhausted.

END.