http://pshaw.pbwiki.com/ A wiki for my personal source code. en http://pshaw.pbwiki.com/feedlogo.gif http://pbwiki.com/ PBwiki 1.3.8 support@pbwiki.com http://pshaw.pbwiki.com/cs111_fall2008_september29 email.hidden@example.com (pshaw) pshaw edited cs111_fall2008_september29 Answer any questions the students have regarding the homework assignment.
Review from last class
Max and Min of 3 numbers
Boolean
Boolean.parseBoolean(String s) Note: only evaluates true when string is "true"
The most useful feature of the Wrapper classes is that most of them have the ability to convert numbers found in Strings into a primitive data structure (like int).
This allows us to essentially to read everything in as a String data type and convert it to a number later. In the next section, we will see an example where we are forced to use this.
String some_text = "42"; int answer = Integer.parseInt(some_text); // "42" is converted to the numerical 42. String some_value = "3.1415"; double pi = Double.parseDouble(some_value); // "3.1415" is converted to the floating point value 3.1415
The Wrapper classes can also store values, just like the primitive data types.
Integer a = 10;
To be perfectly honest, I never]]> Mon, 29 Sep 2008 09:51:11 +0000 mod http://pshaw.pbwiki.com/cs111_fall2008_september29 email.hidden@example.com (pshaw) pshaw edited cs111_fall2008_september29 System.out.println("The smallest value is"+Math.min(Math.min(a,b),c));
System.out.println("The largest value is"+Math.max(Math.max(a,b),c));
<verbatim>
!! PowersPowers of 2
<verbatim> 2
System.out.println(Math.pow(2,0)); // 1.0
System.out.println(Math.pow(2,1)); // 2.0
]]> Mon, 29 Sep 2008 09:22:08 +0000 mod http://pshaw.pbwiki.com/cs111_fall2008_september29 email.hidden@example.com (pshaw) pshaw edited cs111_fall2008_september29 Boolean
Boolean.parseBoolean(String s) Note: only evaluates true when string is "true"
Dialog Boxes
Requires you have this line:
import javax.swing.JOptionPane;
String JOptionPane.showInputDialog(null, String message);
]]> Mon, 29 Sep 2008 01:18:20 +0000 mod http://pshaw.pbwiki.com/cs111_fall2008_september29 email.hidden@example.com (pshaw) pshaw added cs111_fall2008_september29

! Review from last class

!! Max and Min of 3 numbers


double a, b, c;

System.out.print(\"A=\");
a = scan.nextDouble();

System.out.print(\"B=\");
b = scan.nextDouble();

System.out.print(\"C=\");
c = scan.nextDouble();

System.out.println(\"The smallest value is\"+Math.min(Math.min(a,b),c));
System.out.println(\"The largest value is\"+Math.max(Math.max(a,b),c));


!! Powers of 2


System.out.println(Math.pow(2,0)); // 1.0
System.out.println(Math.pow(2,1)); // 2.0
System.out.println(Math.pow(2,2)); // 4.0
System.out.println(Math.pow(2,3)); // 8.0
System.out.println(Math.pow(2,4)); // 16.0
System.out.println(Math.pow(2,5)); // 32.0
System.out.println(Math.pow(2,6)); // 64.0
System.out.println(Math.pow(2,7)); // 128.0


! Wrapper Classes

Each of the eight primitive data types have what\'s called a \"Wrapper Class\". The names of these classes are identical to the names of their primi]]> Mon, 29 Sep 2008 01:15:39 +0000 add http://pshaw.pbwiki.com/cs111_fall2008 email.hidden@example.com (pshaw) pshaw edited cs111_fall2008 cs111_fall2008_september22 - Fun with Random Numbers
cs111_fall2008_september24 - The Math Library
cs111_fall2008_september29 - Message Boxes and Wrapper Classes
]]> Mon, 29 Sep 2008 00:16:51 +0000 mod http://pshaw.pbwiki.com/cs111_fall2008_september24 email.hidden@example.com (pshaw) pshaw edited cs111_fall2008_september24 Object Field
You can tell it's an object because it begins with a lowercase letter and a field because there is no () after it
System
System controls the Input/Output operations and things related to your operating system. There are three items you need to remember:
System.in
Defines Keyboard Input
System.out
Defines Screen Output
System.exit(int number)
A method which abort your program. The number input should either be 0 (meaning a normal exit) or 1 (meaning an exit in response to an error
The Math Class
double
Math.E
Field which evaluates to 2.71828183
double
Math.PI
Field which evaluates to 3.14159265
double
Math.abs(double num)
Returns the absolute value of num
double
Math.long(double num)
Returns the natural logarithm of num
double
Math.min(double a, double b)
Returns either a or b, whichever is smaller
double
Math.max(double a, double b)
Returns either a or b, whichever is larger
double
Math.pow(double base,]]> Sun, 28 Sep 2008 23:40:13 +0000 mod http://pshaw.pbwiki.com/cs111_fall2008_september24 email.hidden@example.com (pshaw) pshaw added cs111_fall2008_september24

\"Politics is applesauce\" -Will Rogers

! Identifying Fields and Classes

Classes always begin with an uppercase letter. Objects should always begin with a lowercase letter.

|Example|Name|Description|
|ClassName.method()|Class Method|You can tell it\'s a class because it begins with an uppercase letter and a method because it has the () after it|
|object_name.method()|Object Method|You can tell it\'s an object because it begins with a lowercase letter and a method because it as () after it|
|ClassName.field|Class Field|You can tell it\'s a class because it begins with an uppercase letter and a field because there is no () after it|
|object_name.field|Object Field|You can tell it\'s an object because it begins with a lowercase letter and a field because there is no () after it|
]]> Sun, 28 Sep 2008 21:54:40 +0000 add http://pshaw.pbwiki.com/cs111_fall2008_september24 email.hidden@example.com (pshaw) pshaw renamed cs111_fall2008_september23 cs111_fall2008_september22 ]]> Sun, 28 Sep 2008 21:49:30 +0000 mv http://pshaw.pbwiki.com/cs111_fall2008 email.hidden@example.com (pshaw) pshaw edited cs111_fall2008 cs111_fall2008_september17 - Strings
cs111_fall2008_september19 - Number formatting and System.out.printf
cs111_fall2008_september23cs111_fall2008_september22 - Fun with Random Numbers Numbers
cs111_fall2008_september24 - The Math Library
]]> Sun, 28 Sep 2008 21:49:08 +0000 mod http://pshaw.pbwiki.com/vim email.hidden@example.com (pshaw) pshaw edited vim $
end of line
#G(number)G
Go To Line Number. to line (number). (Leave off number for last line of file.)
Note: Prefix a cursor movement command with a number to repeat it. For example, 4j moves down 4 lines.
Starting Insert Mode
]]> Tue, 23 Sep 2008 08:32:29 +0000 mod http://pshaw.pbwiki.com/cs111_fall2008_september23 email.hidden@example.com (pshaw) pshaw edited cs111_fall2008_september23 Random random = new Random();
Here are the interesting methods.
1 random.next() random.next(int bits) - Generates a 0 or a 1 random numbers of exactly 'bits' bits.
]]> Mon, 22 Sep 2008 01:28:09 +0000 mod http://pshaw.pbwiki.com/cs111_fall2008_september23 email.hidden@example.com (pshaw) pshaw added cs111_fall2008_september23

! Make corrections on homework assignment.

DecimalFormatter will only format decimal numbers. It will not right justify text. Thank you. Printf will format decimals and right justify text. It is better. The book fails to mention Printf. I do not know why.

! Determinism and Computers

Philosophy classes often talk about determinism and nondeterminism.

Determinism is the idea that everything has a prior cause. Even if the prior cause isn\'t exactly clear, it still had a prior cause.
Indeterminism is the idea that not everything has a prior cause. Some things can be without cause.

Philosophers like to debate this stuff because when it comes to people, these are complicated issues. When it comes to computers, they were built to be purely deterministic. Keep that in mind: Computers are deterministic.

This is one of the reasons why most computer scientists believe that true artificial intelligence isn\'t possible: only an indeterministic mechanism can think for itself, and because compute]]> Mon, 22 Sep 2008 01:26:52 +0000 add http://pshaw.pbwiki.com/cs111_fall2008 email.hidden@example.com (pshaw) pshaw edited cs111_fall2008 cs111_fall2008_september17 - Strings
cs111_fall2008_september19 - Number formatting and System.out.printf
cs111_fall2008_september29cs111_fall2008_september23 - Fun with Random Numbers
]]> Mon, 22 Sep 2008 00:29:00 +0000 mod http://pshaw.pbwiki.com/vimrc email.hidden@example.com (pshaw) pshaw edited vimrc filetype plugin on
autocmd FileType * set formatoptions=cqo
autocmd BufRead makefile, Makefile set noexpandtab
autocmd BufRead *.c,*.cpp,*.h,*.java,*.py,*.pl,*.rb,*.scala set autoindent nospell
" I cannot spell these words.
]]> Sat, 20 Sep 2008 00:03:43 +0000 mod http://pshaw.pbwiki.com/vimrc email.hidden@example.com (pshaw) pshaw edited vimrc filetype plugin on
autocmd FileType * set formatoptions=cqo
autocmd BufRead makefile, Makefile set noexpandtab
autocmd BufRead *.c,*.cpp,*.h,*.java,*.py,*.pl,*.rb,*.scala set autoindent nospell
" I cannot spell these words.
]]> Fri, 19 Sep 2008 23:58:53 +0000 mod http://pshaw.pbwiki.com/vimrc email.hidden@example.com (pshaw) pshaw edited vimrc autocmd FileType * set formatoptions=cqo
autocmd BufRead *.c,*.cpp,*.h,*.java,*.py,*.pl,*.rb,*.scala set autoindent nospell
" Common words that need correcting I cannot spell these words.
ab teh the
ab heigth height
]]> Fri, 19 Sep 2008 23:57:43 +0000 mod http://pshaw.pbwiki.com/vimrc email.hidden@example.com (pshaw) pshaw edited vimrc set tabstop=4
set textwidth=0
syntax enablefiletype plugin on
autocmd BufRead *.c,*.cpp,*.h,*.java,*.py,*.pl,*.rb,*.scala FileType * set autoindent formatoptions=cqo
autocmd BufRead *.c,*.cpp,*.h,*.java,*.py,*.pl,*.rb,*.scala set autoindent nospell
" Common words that need correcting
ab teh the
ab seperate separate
ab resturant restaurant
" REQUIRED. This makes vim invoke latex-suite Turn off those annoying placeholders when you open a tex file.
filetype plugin on editing LaTeX files
let g:Imap_UsePlaceHolders = 0
" IMPORTANT: grep will sometimes skip displaying the file name if you
" search in a singe file. This will confuse latex-suite. Set your grep
]]> Fri, 19 Sep 2008 23:54:31 +0000 mod http://pshaw.pbwiki.com/cs111_fall2008 email.hidden@example.com (pshaw) pshaw edited cs111_fall2008 cs111_fall2008_september17 - Strings
cs111_fall2008_september19 - Number formatting and System.out.printf
cs111_fall2008_september29 - Fun with Random Numbers
]]> Fri, 19 Sep 2008 23:08:38 +0000 mod http://pshaw.pbwiki.com/cs111_fall2008_september19 email.hidden@example.com (pshaw) pshaw edited cs111_fall2008_september19 double bread = 3;
double oneThird = 1.0 / 3.0;
double expensive = 1000;
System.out.println("gum is "+pricePattern.format(gum));
System.out.println("milk is "+pricePattern.format(milk));
System.out.println("bread is "+pricePattern.format(bread));
System.out.println("oneThird is "+pricePattern.format(oneThird));
System.out.println("expensive is "+pricePattern.format(expensive));
The three print statements in Java
System.out.println - Prints text and automatically adds a new line on the end
]]> Fri, 19 Sep 2008 01:34:35 +0000 mod http://pshaw.pbwiki.com/cs111_fall2008_september19 email.hidden@example.com (pshaw) pshaw edited cs111_fall2008_september19 System.out.println("Pi is equal to "+pi2decimal.format(Pi));
System.out.println("Pi is equal to "+pi4decimal.format(Pi));
// Let's use it for prices:
DecimalFormat pricePattern = new DecimalFormat("$0.00");
double gum = .25;
double milk = 3.99;
double bread = 3;
double oneThird = 1.0 / 3.0;
System.out.println("gum is "+pricePattern.format(gum));
System.out.println("milk is "+pricePattern.format(milk));
System.out.println("bread is "+pricePattern.format(bread));
System.out.println("oneThird is "+pricePattern.format(oneThird));
The three print statements in Java
System.out.println - Prints text and automatically adds a new line on the end
]]> Fri, 19 Sep 2008 01:31:10 +0000 mod