Introduction to Programming with Fortran
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Practical Exercise 10
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Note that you need all of the information in the lecture to answer all
of the questions; even the earlier ones need features introduced towards
the end.


Question 1
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1.1 Write and test the following program:

    PROGRAM Keys
        PRINT *, 'Abc', 1.23e-6, -456, 'xyz'
    END PROGRAM Keys


1.2 Change the `PRINT *,' to the following (in turn), try to predict
what will happen, and test the program to check:

a)    WRITE (*, *)
b)    WRITE (UNIT=*, FMT=*)
c)    WRITE (UNIT=*, *)
d)    WRITE (*, FMT=*)
e)    WRITE (FMT=*, UNIT=*)
f)    WRITE (*, UNIT=*)
g)    WRITE (FMT=*, *)


Question 2
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2.1 Using list-directed I/O, write a program that reads in two filenames
from the terminal, opens the first one for input and the second for
output, reads a CHARACTER(LEN=8) variable, a REAL(KIND(0.0D0),
DIMENSION(5) array and an INTEGER variable from the first, and writes
them to the second.  Check the program works by providing the filenames
"Programs/piffle.data" and "piffle.copy", and checking that the latter
is being created correctly, with the same values (but not formatting).


2.2 Copy the program, change it to use unformatted I/O (except for
reading the filenames, of course), and check it using the files
"Programs/huffle.data" and "huffle.copy".  Run the command

    cmp huffle.data huffle.copy

to check that the files are identical.  [ Note that a very few systems
put timestamps etc. in Fortran unformatted files, so this will not
always work; however, it usually will, and it will on the system you are
using to run this example. ]



Question 3
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3.1 Write a program that opens the file "/dev/tty" (i.e. the screen) for
output, and prints the character string 'Kilroy was here' in the form
"Kilroy was here" (i.e. immediately surrounded by quotation marks) using
list-directed output.  Use the DELIM specifer to do this.


3.2 Repeat 3.1, but not using the DELIM specifer (or using DELIM='none',
as you prefer).


3.3 Extend the program in 3.2 to read a CHARACTER variable of length 20
using list-directed input, and print it as above.  Input 'Kilroy was
here', without the apostrophes, surrounded by apostrophes and surrounded
by quotation marks.  Note the effects.


3.4 Using the same program, input a string so that the result displayed
is "/*',",'*/" (11 characters).


Question 4
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4.1 Using the following array declaration:

    INTEGER :: i
    INTEGER, PARAMETER, DIMENSION(20) :: ints = (/ (i, i = 1, 20) /)

Write a program that prints the odd elements only.  Don't worry about
the formatting, including whether numbers are on one line or separate
lines.  Do this three ways:

a)    Using a DO-loop and writing one element at a time.
b)    Using an implied DO-loop in the I/O statement.
c)    Using array sectioning.


4.2 Repeat question 4.1, printing the even elements in reverse order.


Question 5
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5.1 Using the following array declaration and initialisation:

    INTEGER :: i, j
    INTEGER, DIMENSION(6, 8) :: ints

    DO j = 1,8
        DO i = 1,6
            ints(i,j) = i+10*j
        END DO
    END DO

Write a program that prints only the elements with both indices even,
with the first dimension varying fastest.  Don't worry about the
formatting, including whether numbers are on one line or separate lines.

a) Do this using a DO-loop and writing one element at a time.
b) Do this using an implied DO-loop in the I/O statement.
c) Do this using array sectioning, and possibly intrinsics.


5.2 Repeat question 5.1, with the second dimension varying fastest.


Question 6
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6.1 Using list-directed I/O, read the file in Programs/people.data,
which consists of multiple lines, each of which is an integer, a name as
a simple character string of at most 10 characters, and 6 real numbers.
Do not count the lines, but read until end of file, and print out each
line as you read it in.


6.2 Change the program to print out each line in the form of a table
with 4 spaces allowed for the index, and the real numbers printed with 3
digits after the decimal point:
    ' 987: Dickon    1.234 2.345 3.456 4.567 5.678 6.789'
Note the colon.  Use a repeat count to do this, and put the format in a
CHARACTER constant.


6.3 Change the program to read all of the data into three arrays, an
INTEGER one of dimension 20, a CHARACTER*10 one of dimension 20 and a a
REAL one of dimension (6,20).  Then print the data out as a table in a
single WRITE statement.


6.4 Change the format to add a header line "Personnel data"; you
still need only a single WRITE statement.


6.5 Change the program in 6.3 to to take the exponent (the EXP function)
of the second, fourth and sixth numbers for each entry, and change the
format to use ES format for those.