Stepwise Refinement Wirth(1971): Divide and conquer A top-down technique for decomposing a system from preliminary design specification of functionality into more elementary levels Program construction consists of sequence of refinement steps Use a notation natural to problem as long as possible Refine function and data in parallel Each refinement step implies design decisions. Should be made explicit cy Leveson, Sept 1999Stepwise Refinement Wirth (1971): "Divide and conquer" A top-down technique for decomposing a system from preliminary design specification of functionality into more elementary levels. Program construction consists of sequence of refinement steps. Use a notation natural to problem as long as possible. Refine function and data in parallel. Each refinement step implies design decisions. Should be made explicit. Copyright Nancy Leveson, Sept. 1999 c �