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Top-down design

(also stepwise design)

Top-down design definition

Top-down design is the process of the decomposition of a system down to its smaller tasks/parts to understand how they function together. In top-down design, the overview of a system is made by specifying but not going into detail about any of the first-level subsystems. Each subsystem is made more precise by splitting it into many different levels, so the overall specification can be broken down into its most basic tasks. After these basic tasks have been discovered, they can be more easily developed as computer modules. The system can be constructed from its constituent parts or modules, which can be easily connected.

Benefits of top-down design

  • Deconstructing the problem into smaller tasks to allow a clearer understanding of how to solve it.
  • The new tasks become progressively less complex and easier to understand as the refinement process progresses.
  • Components of the solution can be reused.
  • Multiple developers or teams can work on the same project without interfering with one another.

See also: task management, bottom-up design