Software Engineering and Testing

122 SOF T WARE ENGINEERING AND TESTING

To design such hierarchies there are two possible approaches: top-down and

bottom-up. The top-down approach starts from the highest-level component

of the hierarchy and proceeds through to lower levels. By contrast, a bottom-

up approach starts with the lowest-level component of the hierarchy and

proceeds through progressively higher levels to the top-level component.

A top-down design approach starts by identifying the major components

of the system, decomposing them into their lower-level components and

iterating until the desired level of detail is achieved. Top-down design

methods often result in ...