Test 1
               Intro to Programming in Perl
               out: Oct 2 2003
               due: by 8:30am on Tues Oct 6
               from: mahoney@marlboro.edu

 -- Rules ---------------------------------------------
 Do all six problems.  Send me your results in an email
 as usual.  You may use your text or other references, 
 including running anything you please in a perl program.
 Don't use other people.  Please do say what sources you used
 for each problem.  Include appropriate comments, 
 tests, and diagnostic output for your code : your
 goal is to make it easy for me to see that you know
 what you're doing.  Topics: basic syntax for variables
 ($scalar, @arrays, %hashes), conditionals (if), 
 loops (while, for), and booleans (and, or, ==, etc),
 command line input (<>) and output (print).  You may
 use subroutines if you like, but I'm not trying to
 test that here, nor am I looking for detailed 
 work with regular expressions.  I'll be out of town
 this weekend but back Sunday night; you can email me
 if you have questions and I'll get back to you then.

 -- 1 -------------
 
 # Find and correct the syntax errors in the following code.

 $a = 2
 b = "The value of a is " , a;
 if ($a = 3) {
    Print "yup, "a" is three.";
 }

 -- 2 -------------

 # Write a short program which assigns ($P,$Q) to 
 # the four possible boolean combinations, namely
 # (true,true), (true,false), (false, true), (false,false),
 # and shows for each that the following two lines are
 # equivalent.  Use appropriate Perl-ish quantities to
 # represent 'true' and 'false'.

    not ($P and $Q)
    (not $P) or (not $Q)

 # By the way, this is a well known fact in logic 
 # that shows that you can use define the logical
 # "or" operation in terms of the logical "and" and "not".

 -- 3 -------------

 # Write two programs that print the integers from 1 to 10,
 # one using a "for" loop, and one using a "while" loop.

 -- 4 -------------

 # Explain what the "push", "pop", "shift", and "unshift"
 # array operations do.  Show an example of each, printing
 # out the array before and after the operation.

 # Show how you can do the same operation as "push" by
 # using an array assignment statement instead.  

 -- 5 -------------

 # Write a short program that asks the user to type an integer
 # from 1 to 5, and then prints out that number as an English
 # word.  A sample dialog would look like this.

   computer>   Type an integer from 1 to 5.
   user>       4
   computer>   You typed 'four'.

 # For full credit do this in two ways, first using "if" and "elsif",
 # and second using a hash, and also complain if the input is not
 # integer from 1 to 5.

 -- 6 -------------

 # Figure out what the following program does.  Explain.
 # (I suggest trying it with various versions of the first line.)
 # Add appropriate comments and replace these variable
 # names with ones that are clearer.

  my @x=('jim','joe','john');
  my $y="";
  for my $z (@x){
    if ($y lt $z){
      $y=$z;
    }
  }
  print "$y\n";