Object oriented programming1 Week 1.pptx

Object oriented programming1 Week 1.pptx

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  WEEK 1 Instructor: Nazish Basir OBJECT ORIENTED PROGRAMMIN G IN JAVA
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  TOPICS • I NT R O D U C T I O N TO O B J E C T O R I E N T E D P R O G R A M M I N G • I N T R O D U C T I O N TO J AVA • I N S TA L L AT I O N O F J AVA • G E N E R A L S T RU C T U R E O F P R O G R A M • RU N N I N G YO U R F I R S T P R O G R A M • VA R I A B L E S A N D DATA T Y P E S • L I T E R A L S
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  OBJECT ORIENTED PROGRAMMING •Programming paradigm based on the concept of objects, which may contain data, in the form of fields, often known as attributes; and code, in the form of procedures, often known as methods. • Object-Oriented Programming (OOP) is a programming language model, which uses Objects and data as core components. • The main idea behind OOP is to represent the data and logic with objects instead of actions or functions.
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  CLASS • The classdefines the shape and nature of an object. • A class is the template or blueprint from which objects are actually made. • A class is also defined as a new data type, a user defined type which contain two things: – Data Member – Methods • A class defines the properties and behaviors for objects. • The description of a number of similar object is also called as a class. • Classes is logical in nature.
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  OBJECT • An objectis an instance of a class. • An object represents an entity in the real world that can be distinctly identified. For example, a student, a desk, a circle, a button, and even a loan can all be viewed as objects. • Object to object communication is done via methods.
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  OBJECT • Software objectsalso have a state and a behavior: – The state of an object (also known as its properties or attributes): – is represented by data fields with their current values. • A circle object, for example, has a data field radius , which is the property that characterizes a circle. • A dog has states -- color, name, breed – The behavior of an object (also known as its actions): – is defined by methods. • To invoke a method on an object is to ask the object to perform an action. • For example, you may define methods named getArea() and getPerimeter() for circle objects. • A dog has behaviors -- wagging the tail, barking, eating.
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  JAVA • Object-oriented programminglanguage • Resembles C++ in many respects. • Architecture-neutral means Java program should be able to run on a any Operating System without recompilation. • Java programs are compiled into machine-independent byte code which is then run within a Java interpreter, which is responsible for executing the byte code instructions. • The Java interpreter is typically referred to as the JavaVirtual Machine (JVM), and it must be present on each computer that runs the program.
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  Source Code (.java) Byte Code (.class) JAVACJAVA Compiler Interpreter Execution COMPILING JAVA
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  ASSIGNMENT •Write a 2page report about Java History. •Include how java changed over time by including versions and releases.
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  INSTALLING JAVA AND WRITINGAND COMPILING YOUR FIRST PROGRAM
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  VARIABLES •Named locations inmemory where you can store values. •Can store one data value at a time •Can change the values •Variable Names (Identifiers) can be short names (like x and y) or more descriptive names (age, sum, totalVolume)
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  DECLARING VARIABLES •Declaring meansgiving a name and a data type to a variable before it can be used. •Syntax: datatype identifier; datatype identifier1, identifier2, ..;
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  INTEGER DATA TYPES Type Size (Bytes) MinValue Max Value byte 1 -128 127 short 2 -32,768 32,767 int 4 - 2,147,483,648 2,147,483,647 long 8 -9,223,372,036,854,775,808 9,223,372,036,854,775,807
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  FLOATING-POINT DATA TYPES Type Size (Bytes ) MaxPositive Non Zero Value MaxValue float 4 1.40239846 x 10-45 3.40282347 x 1038 double 8 4.9406564584124654 x 10-324 1.7976931348623157 x 10308
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  CHARACTER DATA TYPE char •Size:2 Bytes •MinValue:The character encoded as 0000, the null character •MaxValue:The value FFFF which is a special code for “not a character”
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  BOOLEAN DATA TYPE boolean •Canstore only two values, which are expressed using the Java reserved words true and false.
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  THE ASSIGNMENT OPERATOR ANDINITIAL VALUES • When you declare a variable, you can also assign an initial value to the databy using the assignment operator (=) datatype variableName = initialValue; datatype var1=initialValue1, var2=initialValue2 ; • Notice that assignment is right to left.The initial value is assigned to the variable.
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  IDENTIFIERS RULES • Namescan contain letters, digits, underscores ( _ ), and dollar ( $ ) signs • Names should begin with a letter • Names can also begin with $ and _ • Names are case sensitive ("myVar" and "myvar" are different variables) • Names should start with a lowercase letter and it cannot contain whitespace. If the variable name consists of more than one word, then each word after the first should begin with a capital letter. For example, these identifiers are conventional Java variable names: number1, highScore, booksToRead, ageInYears, and xAxis. • Reserved words (like Java keywords, such as int or String) cannot be
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  LITERALS • INTEGER LITRALS: •Can be expressed in decimal(base 10) • Hexadecimal(base 16) : Prefix 0 is used to indicate octal • Octal(base 8) : prefix 0x indicates hexadecimal • Examples: int decimal = 100; int octal = 0144; int hexa = 0x64; • Values of type long that exceed the range of int can be created from long literals by specifying L or l: long var = 1234567654321L
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  LITERALS • FLOATING-POINT LITERALS •A floating-point literal is of type float if it ends with the letter F or f; otherwise its type is double and it can optionally end with the letter D or d. • The floating point types (float and double) can also be expressed using E or e (for scientific notation), double d1 = 123.4; • same value as d1, but in scientific notation double d2 = 1.234e2; float f1 = 123.4f;
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  LITERALS • CHAR LITERALS •Single quote : char ch = ‘N'; • Integral literal: Unicode value in Decimal, Octal and Hexadecimal. char ch = 78; //range is 0 to 65535 char ch = 0116;//range 000000 to 177777 char ch = 'u004E'; // range u0000 to uFFFF • Escape Sequence : char ch = 'n';
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  JAVA ESCAPE SEQUENCE Escape Sequence Description tInsert a tab in the text at this point. b Insert a backspace in the text at this point. n Insert a newline in the text at this point. r Insert a carriage return in the text at this point. f Insert a formfeed in the text at this point. ' Insert a single quote character in the text at this point. " Insert a double quote character in the text at this point. Insert a backslash character in the text at this point.
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  EXERCISE 1: Write aprogram which displays information about you like: Your Name, Fathers Name, Class Roll No., age, and Cell Phone number. EXERCISE 2: Write down a program which has 2 variable ‘a’ and ‘b’ assign them any value and evaluate the following equation: x = a2 + 2ab + b2 Create variable x and Display the result of ‘x’
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  EXERCISE 3:  Declaretwo short variable and try to assign their sum to byte variable and write down what happened. short a=10, b=20; short c = a+b;  Declare a long variable with value with int range then declare another long variable with value outside the range of int. Write down what happened.  Declare a float variable like this and write down what happened. float a = 12.54;  Declare all types of integers and floating point variables and try to give those values outside of their range and then write down the errors.  Create 5 character variable by giving it different hexadecimal codes and write down what characters are shown on screen.  Declare and initialize two character variable with any alphabet value. Then use this statement to print the result and write down what happened. System.out.println (ch1 + ch2);
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  END