Transcript Java Fundamentals - Department of Computer Science

Getting Started
Java Fundamentals
CSC207 – Software Design
Summer 2011 – University of Toronto – Department of Computer Science
Java
• Released in 1995 by Sun Microsystems
• Key characteristics:
– Object Oriented language
– Suitable for web and network programming
– Portable
• Java programs are platform independent
NetBeans IDE
• You can download it, together with JDK,
from:
– http://www.oracle.com/technetwork/java/javas
e/downloads/jdk-netbeans-jsp-142931.html
• Quick Start:
– Create a new project
– Basic Java program structure
– The popular “Hello World” !
Project Management
• We use DrProject
– https://stanley.cdf.toronto.edu/drproject/csc207-2011-05
– Wiki pages
– Code Repository
– Project Ticketing
– Mailing List !
Code Repository
• Checking out from the repository
– Directly to the NetBeans
Team > Subversion > Checkout
– You can check out all of the lecture codes from:
svn co https://stanley.cdf.toronto.edu/svn/csc207-2011-05/All/lectureCode
– Sample Project:
• LectureCode1
Programming Fundamentals
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Keywords
Method
Variable
Constant
Assignment
Comparison
Selections
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Iteration
Comment
Containers
Encapsulation
Scoping
Libraries
– Graphics
– Input / Output
– Network
Java Keywords
Practice Code 1
Write a program which takes two numbers
from the input and prints the result of their
basic numerical calculations
(addition, subtraction, division, reminder)
Improve the output formatting:
\b
\t
\n
\r
\"
\'
\\
backspace
tab
newline
carriage return
double quote
single quote
backslash
Primitive Data Types
• Java is a strictly-typed language
– All variables must first be declared before they can be used
• int x; // variable declaration
• x = 1; // variable assignment
• int y = 2; // variable declaration and assignment
Numeric P.D.Ts
Type
Storage
Min Value
Max Value
127
32,767
2,147,483,647
> 9 x 1018
byte
short
int
long
8 bits
16 bits
32 bits
64 bits
-128
-32,768
-2,147,483,648
< -9 x 1018
float
double
32 bits
64 bits
+/- 3.4 x 1038 with 7 significant digits
+/- 1.7 x 10308 with 15 significant digits
Primitive Data Types
• char – All Unicode characters
uppercase letters
lowercase letters
punctuation
digits
special symbols
control characters
• boolean
– True / False
– Boolean b = true;
• String
– String name = “Hesam”;
– String fullName;
– fullName = name + “Esfahani”;
A, B, C, …
a, b, c, …
period, semi-colon, …
0, 1, 2, …
&, |, \, …
carriage return, tab, ...
Primitive Data Types
• Default Values
Data Type
Default Value (for fields)
byte
0
short
0
int
0
long
0L
float
0.0f
double
0.0d
char
'\u0000'
String (or any object)
null
boolean
false
Methods
• Contains program statements
– Logically cohesive
• Program is composed of classes
• Each class contains
– Methods
– Attributes
Comments
• Java Comments are in three forms:
// this comment runs to the end of the line
/*
this comment runs to the terminating
symbol, even across line breaks
/** this is a javadoc comment
*/
*/
Control Structures
• Conditional Statements
– If - else
– Switch
• Comparison
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–
–
–
–
–
Equals
Not Equal
Greater
Greater or Equal
Less than
Less than or equal
==
!=
>
>=
<
<=
• Logic Operations
– Logical AND
– Logical OR
&&
II
Practice Code cntd. :
Get the operator from
the input, as well.
Practice Code cntd.:
say if the two number
are equal, or the
greater one
Control Structures
• Iteration
– While
– For
– Do - while
Practice Code cntd :
print “a” n times, where
n is the result of
operation