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differeanc between top-down and bottom-up approch

Discussion in 'C++' started by hkp819, Dec 15, 2008.

  1. hkp819

    hkp819 New Member

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    hello friends
    I am confused about the top-down and bottom-up approach can you tell me the difference between the top-down and bottom-up approach.
    thanks:):)
     
  2. imported_xpi0t0s

    imported_xpi0t0s New Member

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    Do you know what each approach means?
    (I just Googled for "top down" and the first hit seemed somewhat relevant)
     
  3. hkp819

    hkp819 New Member

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    hello friends
    now I have find the answer of my question. I found it on the net.
    the right answer is
    Top down design proceeds from the abstract entity to get to the concrete design. Bottom up design proceeds from the concrete design to get to the abstract entity.

    Top down design is most often used in designing brand new systems, while bottom up design is sometimes used when one is reverse engineering a design; i.e. when one is trying to figure out what somebody else designed in an existing system.

    Bottom up design begins the design with the lowest level modules or subsystems, and progresses upward to the main program, module, or subsystem. With bottom up design, a structure chart is necessary to determine the order of execution, and the development of drivers is necessary to complete the bottom up approach.

    Top down design, on the other hand, begins the design with the main or top-level module, and progresses downward to the lowest level modules or subsystems.

    Real life sometimes is a combination of top down design and bottom up design. For instance, data modeling sessions tend to be iterative, bouncing back and forth between top down and bottom up modes, as the need arises.
     

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