Data types and operators and statements

DATA TYPES AND OPERATORS
AND STATEMENTS

Data types
2

Prof. Ashish Bhatia

Byte Ordering
3
JAVA

x86 and
x64
Prof. Ashish Bhatia

Floating Points - float
4

 Float [ 8byte = 64 bits]
 123.45 ? What is exponent and Significand
 31 – Sign Bit [ 1 bit ]
 23-30 – Exponent Field [ 8 bit ]

 0-22 - Significand [23 bit]

Prof. Ashish Bhatia

Floating Points
5

 Float [ 4byte = 32 bits]
Bits 30-23 Bits 0-22 Significand
Exponent

0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Exponent

1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Exponent

1 1 1 1 1 1 1 1 1 Any Non – zero value
Prof. Ashish Bhatia

Floating Points - double
6

Exponent

0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Exponent

1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Exponent

1 1 1 1 1 1 1 1 1 Any non-zero value

Prof. Ashish Bhatia

Super Type and Sub Type Relations
7

double

float

long

int

short char

byte

Prof. Ashish Bhatia

Using Literals
8

 Use l or L for long values else everything is int.
 Use f or F for Float values else everything is double.
 For Octal use 0
 For Hex use 0x or 0X
 used for special characters
 ‘n’ = New Line
 ‘t’ = Tab
 ‘017’ = Character constant

Prof. Ashish Bhatia

Legal Identifiers
9

 Must start with a letter, a currency character ($), or
a connecting character such as the underscore ( _ ).
Identifiers cannot start with a number!
 After the first character, identifiers can contain any
combination of letters, currency characters,
connecting characters, or numbers.
 In practice, there is no limit to the number of
characters an identifier can contain.
 Identifiers in Java are case-sensitive; foo and FOO
are two different identifiers.
Prof. Ashish Bhatia

Example
10

 int _a;
 int $c;
 int ______2_w;
 int _$;
 int this_is_a_very_detailed_name_for_an_;
 int :b;
 int -d;
 int e#;
 int .f;
 int 7g;

Prof. Ashish Bhatia

Unicode Escape in Java
11

 ufour hex number
 u0A85

Prof. Ashish Bhatia

Reference Datatypes
12

 Arrays
 Classes
 Interface
 Enum
 Annotation

Prof. Ashish Bhatia

Operators
13

 Arithmetic Operators
+ - * / %

 Conversion
 Widening
 Sub type to super type
 Narrowing
 Super Type to sub type
 Mixed Conversion

Prof. Ashish Bhatia

Operators
14

 Unary + and –
 String Concatenation

Prof. Ashish Bhatia

Operator
15

 Relational Operator
 < > <= >= == !=
 Logical Operator
 & | ^ ! && ||
 Bitwise Operator
 & | ^ ~ << >> >>>
 Increment and Decrement Operator [ ++ , -- ]
 Conditional Operator (? : )
 Assignment Operator
 instanceof
 new
Prof. Ashish Bhatia

Example
16

 int a = 60; /* 60 = 0011 1100 */
 int c = a << 2; /* 240 = 1111 0000 */
 int c = a >> 2; /* 15 = 1111 */
 int c = a >>> 2; /* 215 = 0000 1111 */

 What is int a = -60?

Prof. Ashish Bhatia

Statements
17

 Conditional
 if, if-else, switch-case
 Loop
 for, while, do-while
 break, continue, return
 Labeled break and continue

Prof. Ashish Bhatia

Brain Teasing Exercise
18

 x*=2+5
 boolean b = 100 > 99;
 5.0 == 5L
 if(x=0) {}
 if(b){}
 if(5 && 6) {}
 int x = 1;
int y=++x; // x++
System.out.println(y);

Prof. Ashish Bhatia

Output
19

 class Test{
public static void main(String[] args) {
int i = 42;
String s =
(i<40)?"life":(i>50)?"universe":"everyth
ing";
System.out.println(s);
}
}

Prof. Ashish Bhatia

Output
20

String s = "";
boolean b1 = true;
boolean b2 = false;
if((b2 = false) | (21%5) > 2) s += "x";
if(b1 || (b2 = true)) s += "y";
if(b2 == true) s += "z";
System.out.println(s);

Prof. Ashish Bhatia

More on Arrays
21

 int [] array; // recommended
 int array[];
 int [5] array; // ERROR
 Declaring an Array
 Constructing an Array
 int array[] = new Array[]
 int array[] = {1,2,3}
 int z[] = new int[] {1,2,3}
 int z[] = new int[3] {1,2,3}
Prof. Ashish Bhatia

Getting user input
22

import java.util.Scanner;
class Scan
{
public static void main(String args[])
{
Scanner s = new Scanner(System.in);
int x = s.nextInt();
System.out.println(x);
x = s.nextInt();
System.out.println(x);
}
}

Prof. Ashish Bhatia

Data types and operators and statements

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