file system

This is a discussion on file system within the C++ Programming forums, part of the General Programming Boards category; if i write some data on file ... let say student.dat .... when i retrieve the data ... it will ...

  1. #1
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    file system

    if i write some data on file ... let say student.dat ....
    when i retrieve the data ... it will retrive everything at the same time ... how am i suppose to modify it so that it can search for the information i need only ?

    for example .... in my student.dat contains

    1 Amy IT
    2 Kim Engineering
    3 Pete Management

    when i retrive the data, it will retrive everything ...

    how am i suppose to modidy the codes so that it will display onli ... for example .. information about Kim ony ?

  2. #2
    and the hat of wrongness Salem's Avatar
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    Well you either

    - read one record at a time, then use say strcmp() on the appropriate field to determine if its the record you're looking for.

    - read the whole file into an array, then use a for loop to step through the array, then use say strcmp() on the appropriate field to determine if its the array element you're looking for.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  3. #3
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    what about those function like ...
    Code:
    seekg()
    seekp()
    tellg()
    tellp()
    at what purpose do they serve ?

  4. #4
    and the hat of wrongness Salem's Avatar
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    If your records are all the same size, then you can do things like

    seek( record_num * sizeof(record) );

    To access an individual record without having to read all the records before it
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  5. #5
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    Code:
    seek( record_num * sizeof(record) );
    mind explaining to me how to use it ... the syntax looks so blur to me ... sorry if i am annoying but i am still new to C++ ...

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