Perl III Problem Set
====================
 
1.  Create a script that divides two numbers provided on the command line.
        Your script should have the following requirements:
	Two numbers are required.
	The numbers have to be positive.
	The divisor cannot be zero.
 
        You should take care of the following in your Perl script
        =========================================================
	Write the quotient to STDOUT
	Write any errors to STDERR
 
        You should take care of the following on the command line in UNIX
        ==================================================================
	Redirect STDOUT to an output file (out.txt)
	Redirect STDERR to an error file (err.txt)
 
2. Open a file using the open function.
        As you read in lines from the file, make all the letters in each line uppercase.
        (There's a built-in Perl function which will do this.)
 
        Open a new file for output using the open function.
	Write the output to this file 
 
3. Open the provided FASTA file. Print the reverse complement of each
    sequence. Make sure to print the output in fasta format including
    the sequence name and a note in the description that this is the
    reverse complement. Print to STDOUT and capture the output into a file
    with a command line redirect '>'.
 
4. Open the provided FASTQ file. Go through each line of the file. Count
    the number of lines and the number of characters per line.
 
    Have your program report the:
         a. total number of lines
         b. total number of characters
         c. average line length 
 
5. Create a script that uses <> to read in the contents of the provided
    text file, Perl_III.nobody.txt. Use the function index() to
 
      a. find the first position of 'Nobody' on every line
      b. find the first position of 'somebody' on every line
 
    Use the warn() function to warn the user that 'somebody is here'
 
** You can look up how to use the index() and warn() functions in your books, google, or from the command line with the perldoc command, or on perldoc.org.

**** EXTRA CREDIT *** 
6.  Create a file of numbers call numbers.txt with the following content:

22
45
1
2
31
32
72
24
 
 
Create a script that processes the numbers.txt as followes:
Here is the pseudo-code:
 
create file myresult.txt and open it for writing output
 
open numbers.txt for reading
 
while (each line of the file numbers.txt) {
 
  if (the number is even) {
 
    if (the number is less than 24) {
 
       print the line to STDOUT
 
    }
 
  }
  else {
 
    compute the factorial of the number
 
    print the factorial to the file myresult.txt (one per line)
 
  }
 
}
 
        a. What will be printed to STDOUT?
        b. What will be the contents of myresult.txt?
        c. Convert the pseudocode above into a real program.