Difference Between Top Down Approach and Bottom Up Approach
The top down and bottoms -up approaches are two approaches that are commonly used in designing any project. Not many understand the differences between these two approaches and this article intends to highlight the features of both to make it easier for the reader to appreciate the two concepts in their entirety.
The top down designs begin with concept to finally achieve a solid design while bottom- up approach is just the opposite as it starts with the design and then moved down to the basic concept of the design. When it comes to creation of a design of any brand new system, the top down approach is generally used. On the other hand, in case of reverse engineering as when it is to understand someone’s design, bottom up technique is used.
Bottom- up approach begins with the basic design module and moves on to highest module or subsystem. We need a graph structure to learn the steps involved in the execution. Drivers are also required to acomplish this type of design.
Top- down approach starts from the top module level and progresses down to the lowest level of the module. In reality, no system is followed very firmly and designers tend to bounce between the two approaches as the need may be.
There are pros and con of both approaches. If we talk about the benefits of a top down approach, it is easy to conceptualize, provides a sense of completeness and it is easy to assess progress at any stage. On the downside, being a UI approach chances of redundancy of business logics is possible.
In bottom- up approach, the user has the advantages of solid business sense, the ability to write good test unit and the ease with which changes can be managed and changed. Its disadvantages are that much effort is required to write test cases and progress can not be verified easily in the middle stages of designing.