Top-down technique / Stepwise Refinement and Algorithms 20/06/2019

Learning Objectives: Explain the top down approach to problem solving / Stepwise Refinement . Turn a: Problem into a mathematical formula. Problem into a series of stages (algorithm). Algorithm into a flow diagram. 20/06/2019

Top-Down Technique / Stepwise Refinement A problem solving technique: The problem is divided up into a number of smaller problems called modules. Each one is solved separately. Then each module is combined to form a solution to the whole problem. 20/06/2019

Algorithm An explained solution to a problem. There are a number of ways of presenting algorithms. 20/06/2019

How do we find the area of a 'house' made up from a square and a triangle? 20/06/2019

Prose (language description) / / Structured English Find the area of the triangle by multiplying the base by the height and halving. Find the area of the rectangle by multiplying the width by the breadth. Then add the area of the triangle and rectangle together. Each sentence is a module. 20/06/2019

Formulae Each formula is a module. AT = ½ BH AR = W + H + W + H BT = Base of the triangle HT = Height of the triangle W = Width of rectangle BR = Breadth of rectangle AT = Area of the triangle AR = Area of the rectangle AT = ½ BH AR = W + H + W + H = 2 * (H + W) Area of the house = AT + AR Each formula is a module. 20/06/2019

Ordered Steps / Structured English Find the height and base of the triangle. Find the area of the triangle by multiplying the height of the triangle by the base of the triangle, and halving. Find the width and breadth of the rectangle. Find the area of the rectangle by adding the width of the rectangle to the breadth of the rectangle, and multiplying by 2. Add the areas of the triangle and rectangle together. Each step is a module. 20/06/2019

Flowchart Ordered steps using arrows to point from one instruction to the next instead of numbers. Find the height and base of the triangle. Find the area of the triangle by multiplying the height of the triangle by the base of the triangle, and halving. Find the width and breadth of the rectangle. Find the area of the rectangle by adding the width of the rectangle to the breadth of the rectangle, and multiplying by 2. Add the areas of the triangle and rectangle together. 20/06/2019

Plenary Explain the top-down approach to problem solving / Stepwise Refinement . 20/06/2019

Top-Down Technique / Stepwise Refinement A problem solving technique: The problem is divided up into a number of smaller problems. Each one is solved separately. Then each one is combined to form a solution to the whole problem. 20/06/2019