Q. What is stepwise refinement?

Stepwise Refinement:-Stepwise Refinement is a top-down design strategy initially proposed by Niklaus Wirth. A program is developed by consecutively refining levels of procedural detail. A hierarchy is developed by decayed a macroscopic statement of function in a stepwise fashion until programming language statements are reached.

Refinement is really a process of elaboration. We start with a statement of function that is defined at a high level of abstraction. That is the statement explains function or information conceptually but provides no information about the internal workings of the function or the internal structure of the information. Refinement reason that the designer to elaborate on the original statement providing more and more detail as each successive refinement occurs.