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R INFORMATION TECHNOLOGY PROJECT REPORT Java programming TOPIC: WRAPPER CLASSES AND NESTING OF METHODS SUMBITTED BY: Aanchal Gupta Bca (Bachelor of Computer Application) Dezyne E’cole College,www.dezyneecole.com

Aanchal Gupta,BCA 2nd year

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Page 1: Aanchal Gupta,BCA 2nd year

R

INFORMATION TECHNOLOGY

PROJECT REPORT

Java programming

TOPIC:

WRAPPER CLASSES AND NESTING OF METHODS

SUMBITTED BY:

Aanchal Gupta

Bca (Bachelor of Computer Application)

Dezyne E’cole College,www.dezyneecole.com

Page 2: Aanchal Gupta,BCA 2nd year

Project report

On

Java program

At

Dezyne e’cole college

Ajmer

Submitted to Dezyne e’cole college

Toward the

Practical fulfillment on

BCA

By

Aanchal Gupta

Dezyne e’cole college

106/10, civil lines, ajmer

Tel-0145-2624679

www.dezyneecole.com

2016-2017

Page 3: Aanchal Gupta,BCA 2nd year

ACKNOWLEDGEMENT

I Aanchal Gupta Student Of Dezyne E’cole College. An Externally

Grateful To Each And Every Individual Who Has Contribute In

Successful Completion Of My Project.

I Express My Gratitude Towards Dezyne E’cole College For Their

Guidelines And Constant Supervision As Well For Providing The

Necessary Information And Support Regarding The Completion Of

Project.

Thank You.

Page 4: Aanchal Gupta,BCA 2nd year

SYNOPSIS

This Project Is A Minor Project Made,Based On The Theoretical

Concept Of Java This Project Has Made Our Basic Concept On JAVA

Strong.

Page 5: Aanchal Gupta,BCA 2nd year

Wrapper Classes:

As pointed out earlier,vectors cannot handle primitive data type like

int,float,char and double. Primative data type may be converted into

Object types by using the wrapper classes contained in the java.lang

Package. Following table shows the simple data types and their

corresponding wrapper class types.

Wrapper Classes For Converting types

Simple Type Wrapper Boolean Boolean

Char Character

Double Double

Float Float

Int Integer

Long long

The wrapper classes have a number of unique methods for handling

primitive data type and objects. They are listed in the following

tables.

Converting primitive number to object number using

constructor method

Constructor calling Conversion Action Integer IntVal=new Integer(i); Primitive integer to Integer object

Float floatVal=new Float(f); Primitive float to Float object

Double DoubleVal=new Double(d); Primitive double to Double object

Long longVal=new Long(l); Primitive long to Long object

Converting object number to primitive number using

typeValue() method

Method calling Conversion action Int i=IntVal.intValue(); Object to primitive integer

Float f=FloatVal.floatVlue(); Object to primitive float

Long l=LongValue.longValue(); Object to primitive long

Double d =DoubleVal.doubleValue(); Object to primitive double

Page 6: Aanchal Gupta,BCA 2nd year

Converting number to string using to string()Method

Method calling Conversion action Str=integer.toString(i); Primitive integer to string

Str=Float. toString(f); Primitive float to string

Str=double. toString(d); Primitive double to string

Str=Long. toString(l); Primitive long to string

Converting string object to numbers object using static

method valeOf()

Method calling Conversion action DoubleVal=Double.ValueOf(str); Converts string to Double object

floatVal=Float.valueOf(str); Converts string to Float object

IntVal=Integer.ValueOf(str); Converts string to Integer object

LongVal=Long.valueOf(str); Converts string to Long object

Converting numeric string to primitive number using parsing

method

Method calling Conversion action Int i=Integer.parseInt(str); Converts string to Primitive integer Float f=float.parselong(str); Converts string to Primitive float Long l=long.parselong(str); Converts string to Primitive long Double d=double.parseDouble(str); Converts string to Primitive double

Page 7: Aanchal Gupta,BCA 2nd year

converting primitive number to object number

Page 8: Aanchal Gupta,BCA 2nd year

Converting object number to primitive number:

Page 9: Aanchal Gupta,BCA 2nd year

Converting number to string:

Page 10: Aanchal Gupta,BCA 2nd year

Converting string object to numeric object

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Converting number to primitive numbers

Autboxing and unboxing

The Autboxing and unboxing feature,introduce in J2SE 5.0,facilitates

the process of handling primitive data types in collections. We can

use this feature to convert primitive data types to wrapper class

types automatically.the compiler generates a code primitive type to

the corresponding wrapper class type and vice versa. For

example,consider the following statement:

Double d_object=98.42;

Double d_primitive=d_object.doubleValue();

Page 12: Aanchal Gupta,BCA 2nd year

Using the Autboxing and unboxing feature,we can rewrite the above

code as:

Double d_ object=98.42;

Double d_primitive=d_object;

How,the java compiler provides restrictions to perform the following

conversions:

1) Convert from null type to any primitive type.

2) Convert to the null type other than the identify conversion.

3) Convert from any class type c to any array type if c is not

object.

Vector without using autoboxing &unboxing

Page 13: Aanchal Gupta,BCA 2nd year

Vector with using autoboxing &unboxing

Nesting of methods

We discussed earlier that a method of a class can be called by an

object of that class (or class itself,in the case of static method)using

the dot operator.however, ther is an exception to this. A method can

be called by using only its name by another method of the class. This

is known as nesting of methods.

The class nesting defines one constructor and two methods, namely

largest() and display(). The method display() calls the method

largest() determine the largest of the two numbers and then

displays the result.

Page 14: Aanchal Gupta,BCA 2nd year

Largest value=50

A method can call any number of methods. It is also poosible for a

called method to call another method. That is, method1 may call

method2,which in turn may call method3.

Page 15: Aanchal Gupta,BCA 2nd year

THANK YOU