applications/inputoutput.doxy

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bool  subdivide false @endcode

    The results from the program are stored in a similar structure. At
    the end of a program, it is possible to write the input and output
    data into one file. The output file has the same syntax and
    structure as the input file and can therefore be used as an input
    file to reproduce the results at a later time. See the <a
    href="#Results">results section</a> for an example.

    @dontinclude inputoutput.cc
    @section commented Commented Program

    The first few lines in a code for concepts are filled with the
    include files. I put the system includes first here.
    @until unistd.h
    Then, there are the Concepts includes: 
    <ul>
    <li>basics.hh for the exception handling code and other things.
    <li>toolbox.hh for the toolbox, including the intput file parser
    and the handling of input and output data.
    </ul>
    Since there are no real computations in the code, no more include files
    from Concepts are needed.
    @until toolbox.hh
    @skip main
    All code in this example is in one large routine, the main program.
    @until main
    @skip uint
    Some default values for the parameters used. \c l and \c p are just two
    variables. If \c debug is set to true, more information is printed to
    screen.
    @until debug
    A big try block to catch exceptions. More and more runtime errors
    in Concepts are reported by throwing an exception.
    @skip try
    @until try
    First, set up the input parameter class: some parameters
    are set up with a default value.
    @skip concepts::InputParser
    @until parameterout
    The variable outputParameter is for easier access to the output
    area. There, the results of the computations can be stored and
    eventually written to disk if necessary.
    @skip input
    @until input
    Prepare an array for values computed later. This array is then
    added to \c table which is able to nicely format the content of
    the different arrays (e.g. for later processing with Gnuplot).
    @skip error
    @until inputfile

    @subsection parsing Command Line Parsing
    Here, we start with the command line parsing. See the man page
    for \c getopt for more information.

    In the second line of the following code fragement, the string
    defines what command line arguments are allowed and if they take a
    parameter (:) or not. The \c switch statement has an entry
    for every command line argument listed in the string. There, the
    parameter is available as \c optarg. The \c default
    target of the \c switch clause prints some
    usage information (ie. help for the command line arguments).

    The parameters are processed in the order they appear on the
    command line. When first specifying an input file with \c -f, the
    values in the file can be overridden with additional command line
    arguments after \c -f.
    @until }
    Print the parameters to show the user what is going on.
    @skip std::cout
    @until --
    @until --
    Next, the parameters from the command line or the input file are
    stored in the respective variables. This is only used for
    abbrevation.
    @skip l
    @until polynomial

    @subsection comp Computations
    Here are some dummy computations to fill the output area with
    content.
    @skip outputParameters.addInt
    @until error

    @section output Output
    Finally, the input and output data are written to disk with some more
    information about the user and the system in the header of the
    file.
    @skip std::cout
    @until delete
    This prints the table and its content to the screen and also
    stores it with high precision in a file suitable for later
    processing with Gnuplot.
    @skip table
    @until }
    Here, all exceptions derived from the base exception class
    (concepts::ExceptionBase) in Concepts are catched and printed. You
    can test this out by not giving the name of the input file on the
    command line. Then the parameter \c parameterout does not exist
    and the library will throw and exception which is caught here.
    @until }
    @until }

    @section Results
    The output of the program called without parameters: @code
[inputoutput]
--
Parameters:
  input file =
string  author  "(empty)"
string  comment "(empty)"
string  parameterout    "inputoutput.out"
string  title   "(empty)"
int     level   0
int     polynomial      1
bool    debug   false
--
--
Writing gathered data to disk: inputoutput.out
ResultsTable(
error   error
0       1
1       0.5
2       0.25
3       0.125
4       0.0625
5       0.03125
6       0.015625
7       0.0078125
8       0.00390625
9       0.00195312
) @endcode

    The program creates the following output files:
    - \c inputoutput.out: @code
/* program:     inputoutput
 * command:     inputoutput
 * input file:
 */
string  author  "(empty)"
string  comment "(empty)"
string  parameterout    "inputoutput.out"
string  title   "(empty)"
int     level   0
int     polynomial      1
bool    debug   false
end
// output starts here
int     nelm    10
array double error {
        0       1
        1       0.5
        2       0.25
        3       0.125
        4       0.0625
        5       0.03125
        6       0.015625
        7       0.0078125
        8       0.00390625
        9       0.00195312
} @endcode
    - \c inputoutput.gnuplot: @code
# error error
0       1
1       0.5
2       0.25
3       0.125
4       0.0625
5       0.03125
6       0.015625
7       0.0078125
8       0.00390625
9       0.001953125 @endcode

    Note the \c end keyword at the end of the input
    part and right before the output part. When reading in this file as
    input file, the parsing stops right there, ie. the previous output
    data is not read in.

    @section complete Complete Source Code
    @author Philipp Frauenfelder, 2004
*/