COP 4331

1
COP 4331 OODP

• Lecture 2

2
Basic Program Structure

• class Weather
• public static void main(String arguments)
• float fah 86
• System.out.println(fah
• " degrees Fahrenheit is ...")
• // To convert Fahrenheit into Celsius
• // Begin by subtracting 32
• fah fah - 32
• // Divide the answer by 9
• fah fah / 9
• // Multiply that answer by 5
• fah fah 5
• System.out.println(fah " degrees
  Celsius\n")
• //

3
TYJ Day 2 Basics.1

• Basic elements of a program
• Language elements
• Variable names
• Declarations
• Data Types
• Initialization
• Constants (final variables)
• Comments
• // to end of line
• / delimited /

4
TYJ Day 2 Basics.2

• Operators
• Classes of operators
• Arithmetic Operators
• Relational and Conditional Operators
• Shift and Logical Operators
• Assignment Operators
• Other Operators
• Expressions, Statements, Blocks

5
TYJ Day 4 Flow Control

• Flow Control
• General Issues
• The while and do-while Statements
• The for Statement
• The if/else Statements
• The switch Statement
• Branching Statements

6
TYJ Day 3 Working with Objects

• Creating Objects
• Declaration, Instantiation, Initialization
• Component reference
• Class (static) variables methods
• Can also use ClassName.field
• Garbage Collection and finalizers

7
TYJ Day 3 Casting

• Casting numeric primitives
• (typename) value
• returns value with new type
• Casting Classes
• (classname) object
• Treat object as having specified class
• Must be a superclass of the object

8
TYJ Day 3 Converting

• Convert primitive to corresponding class
• Class is generally same name, capitalized
• Exceptions Integer, Character
• Recover value with accessor typeValue()
• Example
• Integer dataCount new Integer(i)
• int newCount dataCount.intValue()

9
TYJ Day 3 Comparing Objects Identifying Class

• Comparison with
• Is it the same object?
• Use equals method to compare value
• See EqualsTest
• Identify class of an object
• getClasss(), getClass().Name()
• Compare classes with
• Instanceof binary operator

10
TYJ Day 4 - Arrays

• Arrays
• Creating and Using Arrays
• Multidimensional array is array of arrays
• Rows are not necessarily of same length
• Arrays of Objects
• Arrays of Arrays
• Copying Arrays