Lesson5

I know been a long time since the previous lesson. But just couldn't - had a lot of reading to catch up with. Here you go next lesson - this will be notes on datatypes.

Primitive -

byte - 8 bits - Number - from -127 to +128

short- 16 bits

int - 32 bits

long- 64 bits

float- 32 bit floating point - do not use this for precision values - may cause rounding issues

double- 62 bit floating point

boolean- true/false - like any language

char- strings characters

Data Type	Default Value (for fields)
byte	0
short	0
int	0
long	0L
float	0.0f
double	0.0d
char	'\u0000'
String (or any object)	null
boolean	false

Array Declaration -

int[] anArray; // declares an array of integers

int [10] anArray; // to restrict to 10 rows

Similarly, you can declare arrays of other types:

byte[] anArrayOfBytes; short[] anArrayOfShorts; long[] anArrayOfLongs; float[] anArrayOfFloats; double[] anArrayOfDoubles; boolean[] anArrayOfBooleans; char[] anArrayOfChars; String[] anArrayOfStrings;

2 Dimensional Arrays

String[][] names = {{"Mr. ", "Mrs. ", "Ms. "},

                            {"Smith", "Jones"}};