CSCI 1301 UGA

LIANG

Hardware

tangible parts - parts of the computer systems

Software

programs- set of instructions

Hardware componenets

keyboard, mouse, display screen, printer, a processor and memory

The procesor

processes a programs instructions

simple instructions

its power is speed

memory

holds programs, data for the comp to process and the results of the processing

main memory

used to store the current program and the data the program is using, the results of intermediate calculations.

Usually measured in megabytes

Byte

a quantity of memory

Auxiliary memory

also secondary memory

disk rives, CD’s, DVDs and flashdrives

permanent

measured in gigabytes

bits

is either a 0 or 1

a byte consists of

8 bits

address

the numbered location that the byte resides in

all data is encoded how?

using 1s and 0s

what is the address when several bytes are needed

the first bytes address

files

large groups of bytes in auxiliary memory

files have names

RAM

temp memory (random access memory)

ROM

permanent memory (read only memory)

when files are organized they are called

directories or folders (java programs are stored in files)

program

a set of instructions for a computer to follow

following the instruction is called

running or executing

input

what the user puts in/the data needed to run the program

output

results produced with the input and set of instructions

what does the operating system do

Retrieves and starts program for you

high level languages

H = human. computers cant understand it

low level languages

this is the translated version from high level which computers can understand.c

compliers

translates the program from high to low level language.

• can be expensive and very large to produce

the compiler on the high level language is called

source program

Java compiler

does not translate a java program into assembly language or machine language, instead it gets converted to byte-code

java byte code

can be translated into any machine language so any computer can read it.

interpreter

translates each byte code instruction

Most java programs today are executed using..

Just-in-time where byte code is compiled and saved for later use so it doesn’t have to be re-compiled.

portability of byte code

can be sent over the internet and used anywhere in the world making java suitable for internet applications.

Classes in programing

pieces of a program in javac

class loader

automatically connects the classes together

applications

Regular programs meant to be run on ur comp

applets

little applications meant to be sent to another location on the internet and run there

programmer

the person who writes the program

package

is a library of classes that have been defined already

the items inside the parentheses are called

arguments

variable

something that can be changed and stores data

Statement

instruction in the computer that ends with a semicolon

syntax

the grammar rules for programming.

IDE

integrated development environment

object

the instances of a class that are created to use the attributes and methods of a class

methods are called

actions

The three design principles of OOP

encapsulation, polymorphism and inheritance

encapsulation

hides internal interpretation (void stuff)

polymorphism

Same program can be used for other things in different context

inheritance

higher more inclusive; lower more exclusing (gets more specific as they go down)

algorithms

a means of performing an action

bug

an error in a program

three kinds of error

syntax, runtime and logic

syntax error

grammatical mystics like no semi colon or something (compiler catches it)

runtime error

errors that are detected when ur programing is running but not during compilation

Logic error

human detects it because incorrect output

value

the data stored by the variable

camelCase

the way variables are named

declaring

giving it a type like int/String/Double/Float/Char

class types

used for a class of objects and has both data and methods

Primitive type

simple, non decomposable values sucha s an individual number or individual character

Primitive types (more memory to less memory)

byte - short - int - long - float - double - char - boolean

identifier

a name of the variable

rules for identifiers

• letters

• digits (0-9)

• the underscore character (_)

• the first character cannot be a digit or capital

Keywords or reserved words

can’t be used in identifiers because they already have meaning

initialized

when a variable is declared but not given a value

import.java.util.Scanner

is used to get the users input

Scanner keyboard = new Scanner(System.in);

gives the scanner an obj so later on keyboard.nextLine(); can be used

e notation

this is during float and can also be imprecise

operands

+, -, *, /

precedence rules

first: +,-,!, ++, and --

second: *,/,%

third: + and -

double quote

\”

single quote

\’

backlash

\\

new line

\ n

carriage return

\ r

tab

\ t

javadoc comments

/** and */

lexicographic order

is similar to alphabetical order, but it is based on the order of the characters in the ASCII (and unicode) character set

.compareTo()

a negative number if first part precedes second part, 0 if they are equal and positive if second part precedes the first part

the exit method

used when a situation arises that makes continuing the program pointless. (System.exit(0))

Switch statements

basically an if-else statement on crack with colons

Break statement

after one case if you put break it won’t consider any of the other cases (break;)

Enumeration

lists the values a variable can have making it restrictive

while loop

isn’t always executed if the conditions don’t require it to

do-while loop

will run once even if conditions aren’t met

a loop that repeats without ever ending is called

infinite loop

For loop

executes a loop after a condition is met for a certain number of times

syntax for For loop

(initialization, condition, update)

continue statement

ends current loop iteration and begins the next one (continue;) recommended to avoid

assertion checks

something that says something about the state of the program