CSE 305 Programming Languages Fall, 2003
Professor Shapiro
Homework 7
Maximum Points: 18
Due 9:00 am, Tuesday, November 4, 2003

Copy this file to a text file named hw7.txt, edit into it your
answers, and submit the file via the submit program by the deadline
given above.

1. Do the following parts of exercise 7.9 (page 315-316) of the text.
Instead of superscripts, write the integer to indicate order
immediately after the right parenthesis.  For example, the answer to
	    a + b * c + d
would be written as
            ((a + (b * c)1)2 + d)3

a. (3) a * (b - 1) / c mod d
b. (3) -a or c = d and e
c. (3) a > b xor c or d <= 17

2. (3) Fortran 77 and earlier versions of Fortran do not have
pointers.  However, pointers may be simulated by parallel arrays.
Edit the following program to replace the question marks (`?') with
appropriate integers so that when you compile and run the program, it
prints the 12 months in the correct order starting with "January".
Copy the edited program into a file named months.f.  Compile the
program with the Unix command
     f77 -o months.fout months.f
and then run it with the Unix command
    months.fout

Here's the program:

      Program months

      Character monName*9(12)
      Integer i, firstMonth, nextMonth(12)

      Data monName/"November", "April", "September", "May",
     C             "December", "June", "February", "October", 
     C             "January", "July", "March", "August" /

      Data firstMonth/?/
      Data nextMonth/?,?,?,?,?,?,?,?,?,?,?,?/

      i = firstMonth
 10   If (i .NE. 0) Then
        Print *, monName(i)
        i = nextMonth(i)
        Goto 10
      EndIf
      End

3. (3) Fortran is one of the few current languages that has an
operator (**) for exponentiation.  What is printed by the following
Fortran program?  (Programs compiled by f77, f90, and f95 print the
same number.)

      Program exptest

      Integer i, j, k
      
      j = 2
      k = 4

      i = j ** 2 ** k - 1

      Print *, i

      End

4. (3) The echo.c program you ran for homework 1 reads and echoes
input until it encounters the string "bye".  However, if it reaches
the end of the input file before it encounters the string "bye", it
will loop infinitely.  The function echo.c uses to read input is
scanf("%s", str). If this is evaluated and there is nothing left in
the input file, it will return a value equal to the predefined
constant EOF.  Edit echo.c so that it will print "Good bye." and
terminate if it reaches the end of the input file.  Use a
short-circuited Boolean expression to do this.  There should be only
one occurrence of the statement `printf("Good bye.\n");' in your
program, and the expression `strcmp(str, "bye")==0' should not be
evaluated when EOF is reached.  After testing the program, paste it
here in the hw7.txt file you submit: