java basics

double

always a decimal (can store twice the amount of information that a int can store)

source code

human written code

byte code

java translated source code

machine code

low level code translated by interpreter

logic error

sometimes program does run, but with the wrong result; failure on human coder’s part (ex: 10.0/3 brings back 3.3…5. that is wrong)

syntax/compiler error

misspellings, no ;, failure to comply by java’s rules

runtime/exception error

dividing by 0

naming conventions

can: uppercase, lowercase, numbers, _, $

cannot: start with number, start with an unauthorized symbol, end with an unauthorized symbol

\\

\

\n

new line

\”

“

\t

tab

System.out.println

prints a line than skips to the next line

System.out.print

prints a line only

int

can store an integer (no decimals/doubles)

int/int

always integer

double/double

always double

modular (%) division

brings back remainder/cannot divide by 0 on left or right side

ide

integrated developmental environment

compiler

compiles source code into byte code

interpreter

translates byte code into machine code

editor

where the source code is written

/*

multiline comment

System.out.println(10+5×6" + “string” + 6×6+2);

40string362

int x = 9;

int y = 10;

double z = (double) 9 + 10;

System.out.println(z);

19.0

final int x;

final int x=9;

System.out.println(x);

9

source code extension

.java

byte code extension

.class

boolean x = 2+2==4;

boolean y = 6-2==1;

System.out.println(x);

System.out.println(y);

true

false