Differentiate between
(i) Top-down and Bottom-up programming?
(ii) Structured and Modular programming. 

Ans:
(i) Top-down and Bottom up programming.
Top down method is also known as step-wise refinement. Here the problem is
first divided into main tasks. Each of these is divided into subtasks and so on.
These subtasks should more precisely describe how the final goal is to be
reached. Whereas the Bottom-up programming is just the opposite of the topdown
approach. In this technique, all small related tasks are grouped into a
major task and the main task becomes the main program.
(ii) Structured and Modular programming.
Structured programming means the collection of principles and practices that
are directed toward developing correct programs which are easy to maintain and
easy to understand. It should read like a sequence from beginning to end instead
of branching from later statements to earlier ones and back again. Whereas in
modular programming the modularity of a system can be represented by a
hierarchical structure which has a single main module at level 1 and gives a
brief description of the system. At level 2 the main module refers to a number
of sub program modules the give a more detailed description of the system and
so on. An important aspect in this hierarchical structuring process is the desire
to understand a module at a certain level independently of all other modules at
the same level.