ME 142 Engineering Computation I Fundamentals of Procedural Computer Programming

Key Concepts Algorithm Development Flowcharting

Algorithm A set of instructions for solving a problem A step-by-step procedure for obtaining a solution to a given class of problems Example: recipe

Algorithm Most programs consist of the following simplified algorithm: Input Process Output

Algorithm Example Develop the algorithm to find the area of a rectangle: Input: Enter length, width Process: Multiply length times width to obtain area Area = length * width Output: Display area

Flowcharts A flowchart is a pictorial representation of an algorithm. Steps of the algorithm are enclosed in boxes of various shapes. The flow of control is indicated by lines connecting the boxes. An arrow is placed on each line to indicate direction of flow.

Standard Flowcharting Symbols Terminator box. Used to show both the start and stop of an algorithm. Operation box. Used for computations, assignment statements, definitions, etc. Input/Output box. Used to indicate items to be read or written by the algorithm.

Standard Flowcharting Symbols Decision box. Used to pose questions in determining which branch to follow for the next instruction. Connector circle. Used to connect parts of the flowchart from page to page, etc.

Flowcharting Example Area of a Rectangle Start Enter length, width area = length * width Display area Stop

Flowcharting Guidelines Flowcharts are written to be a guide for writing actual code. The flowchart should have just enough detail for you to code from. Think in terms of small, sequential operations What needs to be done What order, i.e., what must come first, etc