OOP MIDTERM

Java

• created by James Gosling at Sun MicroSystems (subsidiary of Oracle Corporation) and released in 1995

• initially “Greentalk” by James Gosling and its file extension is .gt then after that “Oak”

• in 1995, it was renamed “Java” due to trademark by Oak Technologies

Features of Java

• Simple

• Object Oriented

• Platform Independent

• Secured

• Robust

• Architectural Normal

• Portable

• High Performance

• Distributed

• Multi-threaded

• Dynamic

Variable

• Something that can store a piece of data

• Can also be called as a container that holds any value\

Two Type of Types

1. Class Types

2. Primitive Types

Class Types

A type for objects with both data and methods

Primitive types

A simple, indecomposable values

Constants

are identifiers whose values never change once declared. The general syntax for declaring constants is:

final <type> <identifier> = <literal>;

Casting

is the process of assigning a value or variable of a specific type to a variable of another type.

Example:

double x=10.0 , y=3.0;

int z;

z = (int) (x/y);

Primitive Data Types

1. string

2. boolean

3. char

4. byte

5. short

6. int

7. long

8. float

Assignment Statements

• is to assign a value to a variable

• Use of assignment operator “=”

• Syntax: Variable_name = expression;

Operators

• are symbols that perform logical or mathematical functions on operands such as variables, constants, and objects.

Unary Operators

require only one operand. In Java, there are at least four unary operators: negation (-), bitwise complement (~), increment (++), and decrement (--). These operators change the value of their operand without using an assignment operator (=).

Arithmetic Operators

+ Addition

- Subtraction

* Multiplication

/ Division

% Modulo

++ Increment

-- Decrement

Comparison / Relational Operators

> 

>=

<

<=

==

!= 

Conditional / Logical Operators

! NOT

|| Logical OR

&& Logical AND

Shortcut Assignment Operators

+= Assignment with Addition

-= Assignment with Subtraction

*= Assignment with Multiplication

/= Assignment with Division

%= Assignment with Modulo

if-else Statement

Rank of Operators

Nested if-else

if-else-if

The Switch Statement

Iterations

• Repeating the same code fragment several times

• Java provides three control statements for

  iterations (a.k.a. loops): for, while, and

  do-while.

The while loop

The while loop

The for loop

is a shorthand that combines in one statement initialization, condition, and change:

The do-while loop

break

instructs the program to immediately quit the current iteration and go to the first statement following the loop.

return

instructs the program to immediately quit the current method and return to the calling method.

Nested Loops

A loop within a loop