Q. Explain the concept of bottom-up design?

Bottom up design: This approach make possible a style of design where we decide how to combine these modules to provide larger ones to combine those to provide even larger ones and so on till we arrive at one big module which is the whole of the desired program.

As the design progressed from bottom layer upwards the method is called bottom up design. The major argument for this design is that if we start coding a module soon after its design the chances of recoding is high however the coded module can be tested and design can be validated sooner than a module whose sub modules have not yet been designed.