Top-down and Bottom-up Approaches
Top-down
- Start with a big picture
- From writing program’s perspective more suitable for procedural languages. For example C where in ‘main’ function logic flow is defined and written. Then smaller functions are written to support ‘main’ function
- Generally suitable for smaller programs
Bottom-up
- Start with details first
- From writing program’s perspective more suitable for object oriented languages where objects are defined first and then those objects are linked to carry out desired tasks
- Generally suitable for bigger and complex programs
From overall design perspectives both approaches are used because first end goal based on requirements is to be known. Once destination is known suitable approach can be used for implementation.
