Introduction to Computing Concepts Note Set 19

Design Creating complex software… ▫ Not done by just one person (or two, or three) ▫ Can’t just sit down and start coding and hope that it will turn out ok and do what it’s supposed to do Things to consider ▫ Must develop what the customer wants, NOT what you think they want ▫ How do you find out from non-techy what they want?

When Programming Syntax – rules of the language you’re using ▫ semi-colons go here ▫ braces go there ▫ that has to be capitilized Semantics ▫ how you need to put together the various structures available to you in order to get the job done ▫ “I need a loop that does some checking with conditions in it…” ▫ Not concerned with rules of language, but more with rules of logic

UML Unified Modeling Language Graphical “language” used to model software systems UML 2.0 has 13 different diagrams used in modeling Today: Activity Diagram ▫ Shows activities and actions that describe the way work gets done ▫ Somewhat similar to old-school flow charts

UML Activity Diagram Example Enter User Name Enter Password Show Main Menu [invalid credentials] [valid credentials] Validate credentials

Parts of an Activity Diagram Enter User Name Enter Password Initial Node Every Activity Diagram has exactly One Indicates where to start Activity Activities that occur Don’t have to map to programming constructs Can be high-level or low-level Flow / edge Show the way to progress through the diagram Follow the flows

Parts of an Activity Diagram Show Main Menu [invalid credentials] [valid credentials] Decision One flow entering and several leaving Guard Condition that must evaluate to true in order for that flow to be followed placed in brackets Final Node Indicates the end of the diagram Diagram many have 0 to many final nodes.

Draw an activity diagram to … Make a PB&J Sandwich

Draw an Activity Diagram to … Register for a class on Access.smu (assume you’ve already logged in) (think high – level)