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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
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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 Validate credentials [invalid credentials] [valid credentials] Show Main Menu
Parts of an Activity Diagram Enter User Name • Initial Node • Every Activity Diagram has exactly One • Indicates where to start Enter Password • Flow / edge • Show the way to progress through the diagram • Follow the flows • Activity • Activities that occur • Don’t have to map to programming constructs • Can be high-level or low-level
Parts of an Activity Diagram • Decision • One flow entering and several leaving [invalid credentials] [valid credentials] Show Main Menu • 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)