CSE115: Introduction to Computer Science I

CSE115: Introduction to Computer Science I Dr. Carl Alphonce 219 Bell Hall Office hours: M-F 11:00-11:50 645-4739 alphonce@buffalo.edu

Reminders & Announcements • Final exam: • Monday, 12/14, 11:45 AM – 2:45 PM • CSEUGSA • 115/116/250 Exam Review • Saturday, 12/12 • Time – starting at 1:00 PM • Room – Bell 242

Objects • properties • stored in (private) instance variables • behaviors • defined by (public) methods • class definition is “blueprint” for objects • creation • new + constructor • space allocated on heap • yields a reference to the object

Classes • definition = header + body • header • access control modifier • name • extends clause (optional) • implements clause (optional) • body • instance variable declarations • constructor and method definitions • constructor • basic role is to set initial value of each instance variable

Variable declarations • All variable declarations have: • type • name • Instance variable declarations have: • access control modifier • type • name • Local variable/parameter declarations have: • type • name

Scope • instance variable • entire class body • local variable • from point of declaration to end of method (block) • parameter • entire method body

Lifetime • instance variable • same as object • local variable • duration of method call • parameter • duration of method call

Relationships • composition • association • dependency • generalization • implementation

Methods • definition = header + body • header • access control modifier • return type specification (void or typename) • name • parameter list • body • statements and declarations

Method calls • methods are called on objects • need a reference • reference can be new • as in: new Ant().start(); • or pre-existing • as in: a.start(); • assuming: Ant a = new Ant();

Patterns • Holder • Proxy • State

Primitives • primitives are not objects • eight primitive types: • boolean • floating point • float • double • integral • unsigned: char • signed: byte, short, int, long

Control structure overviewif-else statement if ( <expr> ) <stmt1> else <stmt2> <expr> false true <stmt2> <stmt1>

Control structure overviewif statement if ( <expr> ) <stmt> <expr> true <stmt> false

Control structure overviewwhile statement while ( <expr> ) <stmt> <expr> true <stmt> false

Exercises Check out the ControlStructureExamples project from the LectureCode repository.

CSE115: Introduction to Computer Science I