OODP101_Week2.pptx - Object Oriented Design and Programming...

Object Oriented Design and Programming
Week 2
Kent Institute Australia Pty. Ltd .
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Version 2 – 18
th
December 2015

SLIDE TITLE
Farrell, J. (2017) Programming Logic
and Design, Comprehensive (9th ed.)
Cengage Learning
2

Chapter 2-Variables and their manipulations
Simple input and output
3 Programming Logic and Design, Ninth Edition

Objectives
In this chapter, you will learn about:
•
Declaring and using variables
•
Data types
•
Performing arithmetic operations
•
Declaring and using constants
•
Object Oriented Programming JAVA basics
•
Simple input and output
4 Programming Logic and Design, Ninth Edition

Working with Variables
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Variable are named memory locations
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Contents can vary or differ over time
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Declaration is a statement that provides a variable's:
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Data type- specify the type of data it will holds
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Identifier - name of variable in memory
• Optionally, an initial value
5 Programming Logic and Design, Ninth Edition

Declaring and Using Variables
•
What are data types?
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Data type describes:
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What values can be held by the item
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How the item is stored in memory
• What operations can be performed on the item
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All programming languages support these data types:
• Numeric consists of numbers that can be used in math
•
String is anything not used in math
6 Programming Logic and Design, Ninth Edition

Understanding a Declaration’s Data
Type
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Numeric variable
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Holds digits
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Can perform mathematical operations on it
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String variable
• Can hold text
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Letters of the alphabet
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Special characters such as punctuation marks
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Type-safety
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Prevents assigning values of an incorrect data type
7 Programming Logic and Design, Ninth Edition

Data types in Java
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Java has 8 primitive data types
- Int for integer numbers (26,645445)
- float for floating point numbers (26.5f,6.2f)
- double for floating point numbers (23.6547132654)
- char for characters (“a”,”b”)
- Boolean (True or False)
- long for long integers
- Short for short integers
- Byte
8 Programming Logic and Design, Ninth Edition

Data Types in Java
•
•
Watch this video for understanding data types in better way
9

Understanding a Declaration’s
Identifier
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An identifier is a variable’s name
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Programmer chooses reasonable and descriptive names for variables
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Programming languages have rules for creating identifiers
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Most languages allow letters and digits
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Some languages allow hyphens
• Reserved keywords are not allowed
10 Programming Logic and Design, Ninth Edition

Understanding a Declaration’s
Identifier
(continued -1)
•