1.00 Tutorial 1
Introduction to 1.00
Outline
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Introductions
Administrative Issues
PS#0
PS#1
Java® Fundamentals
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Introductions
• T A & s tudents introduce yourselves
– Name
– Y ear
• P leas e s ign attendance s heet
• P artner ass ignments
Office Hours
• Office hours are held thrice / week
• F eel free to come with ques tions about J ava®,
s oftware, or homework, but...
• Don't come in if you need homework help, and
you have not s erious ly tried to do it on your own.
Y ou will be as ked to leave.
• T utorial S ections : if you need to s witch s ections ,
s end email.
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Course Website
• Certificate problems?
– Have you installed MIT personal certificates?
– Use Netscape instead of Internet Explorer
– For "unknown SSL error (-12227)":
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uninstall Netscape
delete profile folder* (backup bookmarks first)
download and install Netscape 7 from web
get MIT site certificate and MIT personal
certificates (see instructions on course website)
*See http://wp.netscape.com/eng/mozilla/ns62/CCKDocs/profile_appx_cck.htm
for the path to the profile directory under different operating systems
Laptop Problems
• See MIT website for where to go for software
/hardware problems.
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Forte: Basics
• Startup (just double-click once and wait!)
• Make sure the Java® SDK 1.4 API
documentation is installed. If not, get from
http://java.sun.com/j2se/1.4/download.html
(Scroll down to documentation section.)
• To check, type the word "String" in the
Source Editor, right click, and select
"Show Javadoc"
PS #0
• Problem 2: Hand In
• Problem 3: Hello World (get checked off)
• Problem 4: Upload file to your 1.00
homework locker (get checked off)
• Problem 5: set up printing in Forte
– set up Athena printer
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PS#1: in class exercise
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declare a variable
assign a value to a variable
what is a floating point number?
what is a float? a double?
boolean?
assign a value to a boolean
what is a String?
print a string
Math: more exercises
• Declare two ints, add them and print the
result
• Print out the square root of 2
• Print out
(pi to the square root of 2)
• What is the value of the following
expressions (as integers)?
1%3
7%3
1/2
3/2
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Java® Variables
• have a type
• are case sensitive (studentCount is
different from studentcount)
• begin with a letter, underscore, or $:
i, _tmp, $x
• cannot be Java® keywords. The following
are not legal variable names:
for, goto, import, while, do,...
Java® Fundamental Types
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type
boolean (true or false)
byte
char
short
int
long
float
double
bits
1
8
16
16
32
64
32
64
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Examples
int studentCount = 91;
char firstLetter = 'a';
float weight = 180.6F;
double area = Math.PI * 5.0 * 5.0;
boolean enjoy1.00 = true;
boolean xGreaterThanY = x > y;
long theNumberOne = 1L;
double googol = 1E100; /* 10100 */
Conversion between types
• Implicit (automatic) conversion is called
promotion:
int promoted to double
double x = 3.1415 + 2;
• Explicit conversion is called casting
int myAge =
(int)(Math.PI*10.0+4.0);
expression cast to int
this expression is a double (very accurate)
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Type Conversion
• You will need to perform type conversion
often
• Watch out for promotion: very common
source of (hard-to-find) bugs
• Safer to use casting
Promotion rules
Data Type
double
float
long
int
char
short
byte
Allowed Promotions
None
double
float,double
long,float,double
int,long,float,double
int, long,float,double
short,int,long,float,double
Java® is a trademark or registered trademark of Sun Microsystems, Inc. in the United States and other countries.
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