what is top down design

Top-down design is a methodology used in various fields, including software development and CAD, to simplify the development of complex systems by breaking them down into smaller parts. In top-down design, a systems overview is created first, and then it is decomposed into smaller sub-systems. The highest level is known as the main module, top level, or level 0, and it includes a small number of subtasks. The concept behind top-down design is to break up the task that a program executes into a few extensive subtasks. The top-down design must be independent of any programming language and should never incorporate references to library functions or syntactic elements specific to a particular language. The benefits of top-down design include simplifying the development of products with complex interdependencies and relationships between components, saving time and money, and making it easier to make small or large changes to the design.