Pandemonium - Programming

Yagoohoogle

2005-04-03T15:11:00.000-05:00

Now you can search Yahoo and Google all from one page using Yagoohoogle. It will give you a "split-screen" view of the searches, great for comparing search engines. Now, you might say "I use Dogpile. Doesn't this do the same thing?" No, Dogpile lumps in a bunch of other search engines that don't really give you any thing you need. You end up wasting time looking at stuff you don't need. All you need is Google and Yahoo (in that order) and now with Yagoohoogle you can have them.

+MacMan

Runtime analysis of loops

2005-01-06T17:29:00.000-06:00

Prior to introducing sorts and searches, big-oh analysis must be introduced.
Simple way:
"for(int i = 0;i < n;++i)" or "for(int i = n;i > 0;i--)" loop will run on O(n) time.
"for(int i = 1;i < n;n*=3)" or "for(int i = n;i > 0;i/=3)" loop will run on O(log n) time.
Two or more loops: Multiply the runtimes of the individual loops.

Datatypes, The bits and the bytes

2005-01-06T16:59:00.001-06:00

Type Bits

long signed 64
int signed 32
short signed 16
byte signed 8
boolean 1
char unsigned 16
float signed 64
double signed 64

Data is represented internally as 0's and 1's. Java provides several operators that manipulate the internal representation of integer(long, int, short) and boolean variables.
First, the & (bitwise and) operator needs coverage. Let's say you have a problem 23 & 15
Internally, 23 is 00000000000000000000000000010111 and 15 is 00000000000000000000000000001111. In bits, 0 is equivalent to false and 1 is equilavent to true. You and each bit. True and false is false (0). True and true is true(1). False and false is false (0). Your answer will be 00000000000000000000000000000111 (7).
Next, the | (bitwise or) operator. You convert the number to its internal representation, binary representation. Remembering that 1 is true and 0 is false. You or each bit. True or false is true. True or true is true. 23 | 15 = 31 (00000000000000000000000000011111).
Third, the ^ (bitwise exclusive-or,xor) operator. Follow the same rules as the first two operators. This time you xor each bit. Only if the two bits are of different values, one true and one false, will the bit be 1. 23 ^ 15 = 24 (00000000000000000000000000011000).
Fourth, the << (left shift) operator. General form x << n. The answer will be x*2ⁿ That is so long as the numbers do not overflow. Fifth, the >> (right shift) operator. General form x >> n. The answer will be x/2ⁿThis concludes the datatypes and bits lesson.

Object Oriented Programming (OOP) Terms

2005-01-06T16:59:00.000-06:00

Inheritance - deriving features from an existing class. In java, inheritance is signaled by the extends keyword.
Polymorphism - literally "many forms". In java, polymorphism is implemented through interfaces.
Class - template or factory for making objects.
Object - an class that has behavior.

Welcome to Pandemonium Programming

2005-01-04T19:09:00.000-06:00

This site is meant to teach beginning programmers, mainly those on the Computer Science team at my school.