Data Types & Operators Flashcards
Primitive Integer Types
4 - byte, short, int, long
Primitive Floating-Point Types
2 - float, double
Primitive Non-Numeric Types
2 - char, boolean
Number of Primitive Types
8
Bits & Range: byte
8 bits
-128 to 127
Bits & Range: short
16 bits
-32768 to 32767
Bits & Range: int
32 bits
-2,147,483,648 to 2,147,483,647
Bits & Range: long
64 bits
-9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
char assignment uses what kind of quotes
Single quotes
Operator for testing Boolean values
==
Literals
Fixed values (constants) of any primitive type
Default is int
Postfix l or L for long or f or F for Float - 12L, 10.19f
Octal Literals
Number system based on 8, using digits 0-7
Hexadecimal Literals
Base 16 number system, using digits 0-9 plus A-F (10-15)
Prefix 0X or 0x
Binary Literals
Binary number
Prefix 0B or 0b
String Literals
A set of characters enclosed in double quotes
Escape Sequences
A sequence of characters that does not represent itself when used inside a character or string literal, but is translated to a formatting specifier or character that is hard to represent. Backslash prefix.
'
"
\
Single quote
double quote
Backslash escape sequence
\t
\r
\b
Tab
Carriage Return
Backspace Escape Sequence
\n
New line Escape Sequence
\f
Form feed escape sequence- page break
Variable Declaration
type variableName;
Variable Initialization
type varName = value;
Dynamic variable initialization
type varName = expression;
Types of Scope
Class
Method
Nested Scope Visibility: Outer Scope vs. Inner scope
Outer scope variables are visible to inner scope, but not vice versa.
Variable creation & destruction timeline
Variables are created when their scope is entered & destroyed when their scope is left.
Will a variable hold its value outside of its scope?
No
Will a method variable hold its value between calls to the method?
No
Variable lifetime limitation
Its scope
Can a variable declared in an inner scope have the same name as one declared in the outer scope?
No
Logical Operator: OR, AND
|
&
Logical Operator:
XOR (Exclusive Or)
Not
!
Short-Circuit Logical Operators
OR
AND
Evaluate the second operant only when necessary
||
&&
Shorthand Increment Operator:
x+=10;
X = x + 10
What is Automatic type conversion?
Right value is converted to left side type
When does automatic type conversion take place?
When the two types are compatible & the destination type is larger than the source type.
Which primitives have no automatic type conversion?
Char & boolean
What is a cast?
An explicit instruction to convert one type into another.
Cast syntax
(target type) expression
Can you mix different types in an expression?
Yes, as long as they are compatible
Type Promotion Rules: what primitives convert to int when included with an int in an expression?
Char, byte, short
Precedence of Type Promotion for double, long & float
Long
Float
Double
Should you rely on type Promotion or casting?
Casting is more reliable than type promotion rules
